Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter

Free PDF Download of CBSE Physics Multiple Choice Questions for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter. Physics MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Physics Dual Nature of Radiation and Matter MCQs Pdf with Answers to know their preparation level.

Dual Nature of Radiation and Matter Class 12 Physics MCQs Pdf

Dual Nature of Radiation and Matter MCQ Questions with Answers Pdf Question 1. Light of frequency 1.9 times the threshold frequency is incident on a photosensitive material. If the frequency is halved and intensity is doubled, the photocurrent becomes
(a) quadrupled
(b) doubled
(c) halved
(d) zero

Answer/Explanation

Answer: d
Explaination: (d) As vi = 0.95 v0. No photoelectric emission takes place.


Dual Nature of Matter And Radiation Class 12 MCQ Question 2. Threshold wavelength for a metal having work function W0 is X. What is the threshold wavelength for the metal having work function 2W0?
(a) 4λ
(b) 2λ
(c) λ/2
(d) λ/4

Answer/Explanation

Answer: c
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 17


MCQ on Dual Nature of Matter And Radiation Question 3. Radiations of frequency v are incident on a photosensitive metal. The maximum K.E. of the photoelectrons is E. When the frequency of the incident radiation is doubled, what is the maximum kinetic energy of the photoelectrons?
(a) 2E
(b) 4E
(c) E + hv
(d) E – hv

Answer/Explanation

Answer: c
Explaination: (c) Using Einstein’s photoelectric equation hv – w0 = E


4. Maximum kinetic energy (Ek) of a photoelectron varies with frequency (v) of the incident radiation as
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 2
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 3

Answer/Explanation

Answer: d
Explaination: (d) Using Einstein’s photoelectric equation hv = hv0 + Ek


Physics MCQs for Class 11 With Answers Pdf Question 5. The stopping potential V0 for photoelectric emission from a metal surface is plotted along y-axis and frequency v of incident light along x-axis. A straight line is obtained as shown. Planck’s constant is given by
Physics MCQ Questions for Class 12 Pdf Download
(a) slope of the line
(b) product of the slope of the line and charge on electron
(c) intercept along y-axis divided by charge on the electron
(d) product of the intercept along x-axis and mass of the electron

Answer/Explanation

Answer: b
Explaination: (b) Using Einstein’s photoelectric equation


6. The energy of photon of wavelength 450 nm is
(a) 2.5 × 10-17 J
(b) 1.25 × 10-17 J
(c) 4.4 × 10-19 J
(d) 2.5 × 10-19 J

Answer/Explanation

Answer: c
Explaination:
Physics Multiple Choice Questions With Answers for Class 12 Pdf


7. The kinetic energy of an electron is 5 eV. Calculate the de broglie wavelength associated with it. (h = 6.6 × 10-34 Js, me = 9.1 × 10-31 kg)
(a) 5.47 Å
(b) 10.9 Å
(c) 2.7 Å
(d) None of these

Answer/Explanation

Answer: c
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 19


Photoelectric Effect Multiple Choice Questions and Answers Pdf8. The slope of the stopping potential versus ‘ frequency graph for photoelectric effect is equal to
Photoelectric Effect Multiple Choice Questions and Answers Pdf
(a) h
(b) he
(c) h/e
(d) e

Answer/Explanation

Answer: c
Explaination:
(c) Using Einstein’s equation for photoelectric effect
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 20


Class 12 Physics MCQ Chapter Wise Question 9. A proton and an α-particle are accelerated by the same potential difference. The ratio of their de broglie wavelengths (λp, λα) is
(a) 1
(b) 2
(c) √8
(d) \(\frac{1}{\sqrt{8}}\)

Answer/Explanation

Answer: c
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 21


Class 12 Physics MCQ Chapter Wise Question 10. Work function of three metals A, B and C are 4.5 eV, 4.3 eV and 3.5 eV respectively. If a light of wavelength 4000 Å is incident on the metals then
(a) photoelectrons are emitted from A.
(b) photoelectrons are emitted from B.
(c) photoelectrons are emitted from C.
(d) photoelectrons are emitted from all the metals.

Answer/Explanation

Answer: d
Explaination:
(d) Since energy of incident photon
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 22


11. Which of the following figure represents the variation of particle momentum and associated de Broglie wavelength?
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 7

Answer/Explanation

Answer: d
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 23


12. According to Einstein’s photoelectric equation the plot of the kinetic energy of the emitted photo-electrons from a metal vs the frequency of the incident radiation gives a straight line whose slope
(a) depends on the nature of the metal used.
(b) depends on the intensity of the radiation.
(c) depends both on the intensity of the radiation and the metal used.
(d) is the same for all metals and independent of the intensity of the radiation.

Answer/Explanation

Answer: d
Explaination: (d) Since slope = \(\frac{h}{e}\)


13. If K.E. of free electron is doubled, its de Broglie wavelength will change by factor
(a) \(\frac{1}{\sqrt{8}}\)
(b) √2
(c) \(\frac{1}{2}\)
(d) 2

Answer/Explanation

Answer: a
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 24


14. For a given kinetic energy which of the following has smallest de Broglie wavelength?
(a) Electron
(b) Proton
(c) Deutron
(d) a-particle

Answer/Explanation

Answer: d
Explaination:
(d) Since de Broglie wavelength
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 25
particle, mass of ∝-particle is maximum.


15. A particle is dropped from a height H. The de Broglie wavelength of the particle as a function of height is proportional to [NCERT Exemplar]
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 11

Answer/Explanation

Answer: d
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 26


16. A proton, a neutron, an electron and an a-particle have same energy. Then their de Broglie wavelengths compare as [NCERT Exemplar]
(a)λp = λn > λe > λα
(b) λα < λp = λn < λe
(‘C) λe < λp = λn > λα
(d) λe = λp = λn = λα

Answer/Explanation

Answer: b
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 27


17. In photoelectric effect what determines the maximum velocity of electron reacting the collector?
(a) Frequency of incident radiation alone
(b) Work function of metal
(c) Potential difference between the emitter and the collector
(d) All of these

Answer/Explanation

Answer: d
Explaination: (d) As per Einstein’s photoelectric equation


18. A Proton and an a-particle have the same de Broglie wavelength. What is same for both of them?
(a) Mass
(b) Energy
(c) Frequency
(d) Momentum

Answer/Explanation

Answer: d
Explaination: (d) Since λ = \(\frac{h}{p}\), for the same wavelength momentum is also same.


19. The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nucleus with 1 MeV energy is nearly [NCERT Exemplar]
(a) 1.2 nm
(b) 1.2 × 10-3 nm
(c) 1.2 × 10-6 nm
(d) 1.2 × 101 nm

Answer/Explanation

Answer: b
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 28


20. An electron is moving with an initial velocity v = v0i and is in a magnetic field B = B0 j. Then, its de Broglie wavelength [NCERT Exemplar]
(a) remains constant.
(b) increases with time.
(c) decreases with time.
(d) increases and decreases periodically.

Answer/Explanation

Answer: a
Explaination:
(a) F = q(v × B) = F = qvB sin θ. As this force is perpendicular to v and B, so the magnitude of v will not change, i.e. momentum (p = mv) will remain constant in magnitude
De Broglie wavelength λ = \(\frac{h}{m v}\) remams constant
∴ Comparing wavelengths of proton and neutron, mp = mn, hence λp = λn.


21. Who established that electric charge is quantised?
(a) J.J. Thomson
(b) William Crookes
(c) R.A. Millikan
(d) Wilhelm Rontgen

Answer

Answer: c


22. Cathode rays were discovered by
(a) Maxwell Clerk James
(b) Heinrich Hertz
(c) William Crookes
(d) J.J. Thomson

Answer

Answer: c


23. The minimum energy required for the electron emission from the metal surface can be supplied to the free electrons by which of the following physical processes?
(a) Thermionic emission
(b) Field emission
(c) Photoelectric emission
(d) All of these

Answer

Answer: d


24. The phenomenon of photoelectric emission was discovered in 1887 by
(a) Albert Einstein
(b) Heinrich Hertz
(c) Wilhelm Hallwachs
(d) Philipp Lenard

Answer

Answer: b


25. A metal surface ejects electrons when hit by green light but nothing when hit by yellow light. The electrons will be ejected when the surface is hit by
(a) blue light
(b) heat rays
(c) infrared light
(d) red light

Answer

Answer: a


26. Which of the following statements is correct regarding the photoelectric experiment?
(a) The photocurrent increases with intensity of light.
(b) Stopping potential increases with increase in intensity of incident light.
(c) The photocurrent increases with increase in frequency.
(d) All of these

Answer

Answer: a


27. In photoelectric effect, the photocurrent
(a) depends both on intensity and frequency of the incident light.
(b) does not depend on the frequency of incident light but depends on the intensity of the inci-dent light.
(c) decreases with increase in frequency of inci-dent light.
(d) increases with increase in frequency of inci-dent light.

Answer

Answer: b


28. The maximum value of photoelectric current is called
(a) base current
(b) saturation current
(c) collector current
(d) emitter current

Answer

Answer: b


29. In photoelectric effect, the photoelectric current is independent of
(a) intensity of incident light
(b) potential difference applied between the two electrodes
(c) the nature of emitter material
(d) frequency of incident light

Answer

Answer: d


30. In photoelectric effect, stopping potential depends on
(a) frequency of incident light
(b) nature of the emitter material
(c) intensity of incident light
(d) both (a) and (b)

Answer

Answer: d


31. According to Einstein’s photoelectric equation, the graph of kinetic energy of the photoelectron emitted from the metal versus the frequency of the incident radiation gives a straight line graph, whose slope
(a) depends on the intensity of the incident radi-ation.
(b) depends on the nature of the metal and also on the intensity of incident radiation.
(c) is same for all metals and independent of the intensity of the incident radiation.
(d) depends on the nature of the metal.

Answer

Answer: c


32. The figure shows stopping V0A potential V0 and frequency o for two different metallic surfaces A and B. The work function of A, as compared to that of B is
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter
(a) less
(b) more
(c) equal
(d) nothing can be said

Answer

Answer: a


33. Which phenomenon best supports the theory that matter has a wave nature?
(a) Electron momentum
(b) Electron diffraction
(c) Photon momentum
(d) Photon diffraction

Answer

Answer: b


34. The figure shows the variation of photocurrent with anode potential for a photosensitive surface for three different radiations. Let Ia, Ib and Ic be the intensities and va, vb. and vcbe the frequencies for the curves a, b and c respectively. Then the correct relation is
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 5
(a) va = vb and Ia ≠ Ib
(b) va = vc and Ia = Ic
(c) va = vb and Ia = Ib
(d) vb = vc and Ib = Ic

Answer

Answer: a


35. The photoelectric effect can be explained by
(a) Corpuscular theory of light
(b) Wave nature of light
(c) Bohr’s theory
(d) Quantum theory of light

Answer

Answer: d


36. Work function of metal is
(a) the minimum energy required to free an electron from surface against coulomb forces.
(b) the minimum energy required to free an », nucleon.
(c) the minimum energy to ionise an atom.
(d) the minimum energy required to eject an electron orbit.

Answer

Answer: a


37. The rest mass of a photon of wavelength X is
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 8

Answer

Answer: a


38. Photoelectric effect is based on the law of conservation of
(a) energy
(b) mass
(c) linear momentum
(d) angular momentum

Answer

Answer: a


39. Einstein’s photoelectric equation is:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 9
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 10

Answer

Answer: a


40. In photoelectric effect, the number of photoelectrons emitted is proportional to
(a) intensity of incident beam. –
(b) frequency of incident beam.
(c) velocity of incident beam.
(d) work function of photo cathode.

Answer

Answer: a


41. Which of the following shows particle nature of light?
(a) Photoelectric effect
(b) Refraction
(c) Interference
(d) Polarisation

Answer

Answer: a


42. Relativistic corrections become necessary when the expression for the kinetic energy 1/2 mv², becomes comparable with mc², where m is the mass of the particle. At what de Broglie wavelength, will relativistic corrections become important for an electron?
(a) λ = 10 nm
(b) λ = 10-1 nm
(c) λ = 10-4nm
(d) λ = 10-3 nm

Answer

Answer: c


43. Two particles A1 and A2 of masses m1, m2(m1 > m2) have the same de Broglie wavelength. Then,
(a) their momenta are the same.
(b) their energies are the same.
(c) energy of A1 is greater than the energy of A2
(d) energy of A1 is equal to the energy of A2

Answer

Answer: a


44. Photons absorbed in a matter are converted to heat. A source emitting h photon/sec of frequency v is used to convert 1 kg or ice at 0°C to water at 0°C. Then, the time T taken for the conversion
(a) increases with increasing n, with v fixed
(b) decreases with n fixed, v increasing.
(c) does not remain constant with n and v changing such that nv = constant
(d) increases when the product nv increases.

Answer

Answer: b


45. A particle moves in a closed orbit around the origin, due to a force which is directed towards the origin. The de Broglie wavelength of the particle varies cyclically between two values λ1, λ2 with λ1 > λ2. Which following statements are true?
(a) The particle could not be moving in a circular orbit with origin as centre.
(b) The particle could not be moving in an elliptic orbit with origin as its focus.
(c) When the de Broglie wavelength is λ1 the particle is nearer the origin than when its value is λ2.
(d) When the de Broglie wavelength λ2, the particle is nearer the origin than when its value λ1.

Answer

Answer: d


46. Consider the following statements:
I. According to de Broglie hypothesis, particles have wave-like characteristics.
II. When an electron and a proton have the same de Broglie wavelength, they will have equal momentum.
Which of the above statements is/are correct?
(a) I only
(b) II only
(c) both I and II
(d) neither I nor II

Answer

Answer: c


47. Maximum photoelectric current at particular intensity of incident radiation, which becomes independent of anode potential is known as __________ .

Answer/Explanation

Answer:
Explaination: saturation current


48. Stopping potential is of intensity of incident radiation but proportional to __________ of the radiation.

Answer/Explanation

Answer:
Explaination: independent, frequency


49. Kinetic energy and stopping potential are zero, when frequency of incident radiation is equal to __________ .

Answer/Explanation

Answer:
Explaination: threshold frequency


50. According to Planck’s quantum theory of radiation, an electromagnetic wave travels in the form packets of energy called __________ .

Answer/Explanation

Answer:
Explaination: photon


51. __________ experiment has varified and confirmed the wave nature of electrons.

Answer/Explanation

Answer:
Explaination: Davisson and Germer


52. Photoelectric emission occurs only when the frequency of incident radiation is __________ than threshold frequency.

Answer/Explanation

Answer:
Explaination: greater


53. Photoelectric emission is an __________ process.

Answer/Explanation

Answer:
Explaination: instantaneous


54. De Broglie wavelength associated with an electron beam accelerated through a potential difference V is __________ proportional to √V.

Answer/Explanation

Answer:
Explaination: inversely


55. __________ is the minimum amount of energy required to cause photoelectric emission.

Answer/Explanation

Answer:
Explaination: Wok function


56. Wave associated with the material particle is known as __________ .

Answer/Explanation

Answer:
Explaination: matter wave


57. Name the phenomenon which shows the quantum nature of electromagnetic radiation. [AI2017]

Answer/Explanation

Answer:
Explaination: Photoelectric effect.


58. Define the term ‘threshold frequency’ in relation to photoelectric effect. [Delhi 2019, Foreign 2011]

Answer/Explanation

Answer:
Explaination:
Threshold frequency: For every metal surface, there is a minimum frequency of incident radiation, below which the photoelectric emission does not take place no matter what the intensity of incident radiation is and for how long the radiations are allowed to fall on the metal. This frequency is called threshold frequency.


59. Show the variation of photocurrent with collector plate potential for different frequencies but same intensity of incident radiation. [AI 2017, Foreign 2011]

Answer/Explanation

Answer:
Explaination:
For same intensity but different frequencies v1 > v2 > v3 of incident radiation.
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 29


60. In photoelectric effect, why should the photoelectric current increases as the intensity of monochromatic radiation incident on a photosensitive surface is increased? Explain. [Foreign 2014]

Answer/Explanation

Answer:
Explaination:
An increase in intensity means increase in number of photons and thus, increase in photoelectric current.


61. Show the variation of photocurrent with collector plate potential for different intensities but same frequency of incident radiation. [Delhi 2019, AI 2017, Foreign 2011]

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 30


62. What is the rest mass of a photon?

Answer/Explanation

Answer:
Explaination: The rest mass of a photon is zero.


63. The given graph shows the variation of photoelectric current (I) versus applied voltage (V) for two different photosensitive materials and for two different intensities of the incident radiation. Identify the pairs of curves that correspond to different materials but same intensity of incident radiation. [Delhi 2013]
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 12

Answer/Explanation

Answer:
Explaination: The materials with same intensity of incident light are 1 and 3; 2 and 4.


64. The graph shows the variation of stopping potential with frequency of incident radiation for two photosensitive metals A and B. Which one of the two has higher value of work function? Justify your answer. [Chennai 2019, Dehradun 2019]
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 13

Answer/Explanation

Answer:
Explaination:
As threshold frequency of metal A is greater, its work function, Φ = hv0, will also be greater than that of B.


65. For a given photosensitive material and with a source of constant frequency of incident radiation, how does the photocurrent vary with the intensify of incident light? [Delhi 2014, AI 2011C]
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 14

Answer/Explanation

Answer:
Explaination:
The photoelectric current increases linearly with the intensity of light as shown in the figure.
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 31


66. Ultraviolet radiations of different frequencies v1 and v2 are incident on two photosensitive materials having work functions W1 and W2 (W1 > W2) respectively. The kinetic energy of the emitted electrons is same in both the cases. Which one of the two radiations will be of higher frequency?

Answer/Explanation

Answer:
Explaination:
v1 > v2. As W1 > W2 and K.E. is same. From the relation,
hv = hv0 + \(\frac{1}{2}\) mv²
and hv0 = W= work function


67. Two beams, one of red light and the other of blue light, of the same intensity are incident on a metallic surface to emit photoelectrons. Which one of the two beams emits electrons of greater kinetic energy? [HOTS]

Answer/Explanation

Answer:
Explaination:
The blue light emits the electrons of greater K.E., as vb > vr.


68. Can non-metals show photoelectric effect? [HOTS]

Answer/Explanation

Answer:
Explaination: Yes, when they are exposed to electromagnetic radiations of higher frequency.


69. A photosensitive surface emits photoelectrons when red light falls on it. Will the surface emit photoelectrons when blue light is incident on it? Give reason. [Foreign 2017]

Answer/Explanation

Answer:
Explaination:
Since condition for photoemission is \(\frac{h c}{\lambda} \geq \phi_{0}\) (work function) and λB < λR hence, surface will emit photoelectrons.


70. What happens to the wavelength of a photon after it collides with an electron?

Answer/Explanation

Answer:
Explaination: The wavelength of a photon increases.


71. State de Broglie hypothesis. [Delhi 2012]

Answer/Explanation

Answer:
Explaination:
“Particles of matter moving with a given velocity (momentum) can display wave-like properties”.
\(\lambda=\frac{h}{p}\)


72. Write the expression for the de Broglie wavelength associated with a charged particle having charge q and mass m, when it is accelerated by a potential V. [AI2013]

Answer/Explanation

Answer:
Explaination:
De Broglie wavelength associated with a charged particle when accelerated by a potential V is given by
\(\lambda=\frac{h}{p}=\frac{h}{\sqrt{2 m q V}}\)
where m = mass of charge particle and q = charge on the particle


73. A proton and an electron have same kinetic energy. Which one has smaller de Broglie wavelength and why? [AI 2012]

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 32


74. Show on a graph the variation of the de Broglie wavelength (λ) associated with an electron with the square root of accelerating potential (V). [Delhi 2019, Similar Panchkula 2019, Foreign 2012]
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 15

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 33


75. Write the relationship of de Broglie wavelength λ associated with a particle of mass m in terms of its kinetic energy E. [Delhi 2011C]

Answer/Explanation

Answer:
Explaination:
The required relation is given by \(\lambda=\frac{h}{\sqrt{2 m E}}\)


76. Name an experiment which shows wave nature of electrons. Which phenomenon was observed in this experiment using an electron beam?

Answer/Explanation

Answer:
Explaination:
Experiment: Davisson and Germer
Phenomenon: Diffraction


77. Two lines, A and B, in the plot given below show the variation of de Broglie wavelength, λ versus 1/√V, where V is the accelerating potential difference, for two particles carrying the same charge. Which one of two represents a particle of smaller mass?
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 16

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 34


78. The de Broglie wavelength of a particle of kinetic energy K is λ. What would be the wavelength of the particle, if its kinetic energy were K/4 [HOTS]

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 35


79. An electron and alpha particle have the same kinetic energy. How are the de Broglie wavelength associated with them related? [Similar Delhi 2019]

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 36


80. Two metals A and B have work functions 2 eV and 5 eV respectively. Which metal has lower threshold wavelength?

Answer/Explanation

Answer:
Explaination:
Metal with work function 5 eV has lower threshold wavelength, i.e. metal B.


81. Show graphically how the maximum kinetic energy of electrons emitted from a photosensitive surface varies with the frequency of incident radiations.

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 11 Dual Nature of Radiation and Matter 37


82. What is the charge on metal in the photoelectric experiment?

Answer/Explanation

Answer:
Explaination: It will possess positive charge as it has lost electrons.


83. What is the momentum of a photon of
(i) frequency v, and (ii) wavelength λ?

Answer/Explanation

Answer:
Explaination:
(i) Energy of photon
E = hv = mc²
∴ Momentum of a photon = mc = \(\frac{hv}{c}\)
(ii) The momentum of a photon of wavelength λ is p = \(\frac{h}{\lambda}\).
where h is the Planck’s constant.


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Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics

Free PDF Download of CBSE Physics Multiple Choice Questions for Class 12 with Answers Chapter 10 Wave Optics. Physics MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Physics Wave Optics MCQs Pdf with Answers to know their preparation level.

Wave Optics Class 12 Physics MCQs Pdf

MCQ on Wave Optics Class 12 Question 1. Resolving power of telescope can be increased by increasing
(a) the wavelength
(b) the diameter of objective
(c) the diameter of eyepiece
(d) the focal length of eyepiece

Answer/Explanation

Answer: b
Explaination:
(b) The diameter of objective as R.P. of a telescope = \(\frac{D}{1.22 \lambda}\) R.P. is proportional 1.22 A to diameter of objective (D).


Wave Optics MCQ Question 2. Polarisation of light proves
(a) corpuscular nature of light.
(b) quantum nature of light.
(c) transverse wave nature of light.
(d) longitudinal wave nature of light.

Answer/Explanation

Answer: c
Explaination: (c) transverse wave nature of light.


Wave Optics Class 12 MCQ Question 3. The wavefront due to a source situated at infinity is
(a) spherical
(b) cylindrical
(c) planar
(d) circular

Answer/Explanation

Answer: c
Explaination: (c) The wavefront due to any source situated at infinity is planar.


4. A laser beam is coherent because it contains
(р) waves of several wavelengths.
(b) incoherent waves of a single wavelength.
(c) coherent waves of several wavelengths
(d) coherent waves of a single wavelength.

Answer/Explanation

Answer: d
Explaination: (d) coherent waves of a single wavelength.


MCQ on Wave Optics Pdf Question 5. If two sources have a randomly varying phase difference Φ(t), the resultant intensity will be given by
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 1

Answer/Explanation

Answer: c
Explaination:
(c) 2I0, For two incoherent sources, the resultant intensity at every point is just twice of the two individual intensities.


6. According to Huygens’ principle, light is a form of
(a) particle
(b) rays
(c) wave
(d) radiation

Answer/Explanation

Answer: c
Explaination:
(c) According to Huygens’ principle, light travels in the form of a longitudinal wave.


Optics MCQ 14 Question 7. Two coherent monochromatic light beams of intensities I and 41 superimpose. The maximum and minimum possible intensities in the resulting beam are:
(a) 5I and I
(b) 5I and 3I
(c) 3I and I
(d) 9I and I

Answer/Explanation

Answer: d
Explaination:
Physics MCQs For Class 12 Chapter Wise With Answers Pdf Download


Wave Optics Questions with Answers Pdf Question 8. What is path difference for destructive interference?
(a) nλ
(b) n(λ +1)
(c) (2n + 1)\(\frac{\lambda}{2}\)
(d) (n +1)\(\frac{\lambda}{2}\)

Answer/Explanation

Answer: c
Explaination:
(c) (2n + 1)\(\frac{\lambda}{2}\) For destructive interference, the path difference is an odd multiple of λ/2.


9. When exposed to sunlight, thin films of oil on water of ten exhibit brilliant colours due to the phenomenon of
(a) interference
(b) diffraction
(c) dispersion
(d) polarisation

Answer/Explanation

Answer: a
Explaination: (a) interference


10. What happens, if the monochromatic light used in Young’s double slit experiment is replaced by white light?
(a) No fringes are observed.
(b) All bright fringes become while.
(c) All bright fringes have colour between violet and red.
(d) Only the central fringe is white and all other fringes are coloured.

Answer/Explanation

Answer: d
Explaination: (d) At central bright fringes of all wavelength overlap to produce white central fringe.


11. When compact disk is illuminated by a source of white light, coloured lines are observed. This is due to
(a) dispersion
(b) diffraction
(c) interference
(d) refraction

Answer/Explanation

Answer: b
Explaination: (b) The small ripples on the compact disc split white light into the constituent colours.


12. An unpolarised beam of intensity I0 is incident on a pair of nicols making angle of 60° with each other. The intensity of right emerging from the pair is
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 2

Answer/Explanation

Answer: d
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 9


13. When unpolarised light beam is incident from air onto glass (n = 1.5) at the polarising angle.
(a) Reflected beam is polarised completely
(b) Reflected and refracted beams are partially polarised
(c) Refracted beam is plane polarised
(d) Whole beam of light is refracted

Answer/Explanation

Answer: b
Explaination: (b) The reflected fight is completely polarised.


14. Resolving power of microscope depends upon
(a) wavelength of light used (directly proportional)
(b) wavelength of light used (inversely proportional)
(c) frequency of light used
(d) focal length of objective

Answer/Explanation

Answer: b
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 10


15. The phenomenon of interference is based on
(a) conservation of momentum.
(b) conservation of energy.
(c) conservation of momentum and energy.
(d) quantum nature of light.

Answer/Explanation

Answer: b
Explaination: (b) conservation of energy


16. A double slit interference experiment is carried out in air and the entire arrangement is dipped in water. The fringe width
(a) increases
(b) decreases
(c) remains unchanged.
(d) fringe pattern disappears.

Answer/Explanation

Answer: b
Explaination:

(b) Decreases
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 11


17. In Young’s double slit experiment, if the monochromatic source of yellow light is replaced by red light, the fringe width
(a) increases
(b) decreases.
(c) remains unchanged.
(d) the fringes disappear

Answer/Explanation

Answer: a
Explaination: (a) Increases, as fringe width β ∝ λ(λyellow < λed)


18. In Young’s double-slit experiment, the intensity at the central maximum is I0 if one of the slit is covered, then the intensity at the central maximum become:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 3

Answer/Explanation

Answer: c
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 12


19. The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index n) is
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 4

Answer/Explanation

Answer: d
Explaination:
(d) Polarising angle,
i = tan-1 (n), (Brewster’s law)


20. In Young’s double-slit experiment, the intensity is I at a point, where the path difference is \(\frac{\lambda}{6}\) (λ – wavelength of light used). If I0 denotes the maximum intensity then \(\frac{I}{I_{0}}\) is equal to
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 5

Answer/Explanation

Answer: c
Explaination:
(c) As path difference,
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 13


21. The idea of secondary wavelets for the. propagation of a wave was first given by
(a) Newton
(b) Huygens
(c) Maxwell
(d) Fresnel

Answer

Answer: b


22. Light propagates rectilinearly, due to
(a) wave nature
(b) wavelengths
(c) velocity
(d) frequency

Answer

Answer: a


23. Which of the following is correct for light diverging from a point source?
(a) The intensity decreases in proportion with the distance squared.
(b) The wavefront is parabolic.
(c) The intensity at the wavelength does not depend on the distance.
(d) None of these.

Answer

Answer: a


24. The refractive index of glass is 1.5 for light waves of X = 6000 A in vacuum. Its wavelength in glass is
(a) 2000 Å
(b) 4000 Å
(c) 1000 Å
(d) 3000 Å

Answer

Answer: b


25. The phenomena which is not explained by Huygen’s construction of wavefront
(a) reflection
(b) diffraction
(c) refraction
(d) origin of spectra

Answer

Answer: d


26. A laser beam is used for locating distant objects because
(a) it is monochromatic
(b) it is not chromatic
(c) it is not observed
(d) it has small angular spread.

Answer

Answer: d


27. Two slits in Young’s double slit experiment have widths in the ratio 81 :1. The ratio of the amplitudes of light waves is
(a) 3 :1
(b) 3 : 2
(c) 9 :1
(d) 6:1

Answer

Answer: c


28. When interference of light takes place
(a) energy is created in the region of maximum intensity
(b) energy is destroyed in the region of maximum intensity
(c) conservation of energy holds good and energy is redistributed
(d) conservation of energy does not hold good

Answer

Answer: c


29. In a double slit interference pattern, the first maxima for infrared light would be
(a) at the same place as the first maxima for green light
(b) closer to the centre than the first maxima for green light
(c) farther from the centre than the first maxima for green light
(d) infrared light does not produce an interference pattern

Answer

Answer: c


30. To observe diffraction, the size of the obstacle
(a) should beX/2, where X is the wavelength.
(b) should be of the order of wavelength.
(c) has no relation to wavelength.
(d) should be much larger than the wavelength.

Answer

Answer: b


31. The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of the order of
(a) 106 rad
(b) 10-2 rad
(c) 10-4 rad
(d) 10-6 rad

Answer

Answer: d


32. The velocity of light in air is 3 * 108 ms-1 and that in water is 2.2 * 108 ms” . The polarising angle of incidence is
(a) 45°
(b) 50°
(c) 53.74°
(d) 63

Answer

Answer: c


33. An optically active compound
(a) rotates the plane of polarised light
(b) changes the direction of polarised light
(c) does not allow plane polarised light to pass through
(d) none of these

Answer

Answer: a


34. Consider a light beam incident from air to a glass slab at Brewster’s angle as shown in Figure.
A polaroid is placed in the path of the emergent ray at point P and rotated about an axis passing through the centre and perpendicular to the plane of the polaroid.
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 6
(a) For a particular orientation there shall be darkness as observed through the polaroid.
(b) The intensity of light as seen through the polaroid shall be independent of the rotation.
(c) The intensity of light as seen through the polaroid shall go through a minimum but not zero for two orientations of the polaroid.
(d) The intensity of light as seen through the polaroid shall go through a minimum for four orientations of the polaroid. [NCERT Exemplar]

Answer

Answer: c


35. Consider sunlight incident on a slit of width 104 A. The image seen through the slit shall
(a) be a fine sharp slit white in colour at the centre.
(b) a bright slit white at the centre diffusing to zero intensities at the edges.
(c) a bright slit white at the centre diffusing to regions of different colours.
(d) only be a diffused slit white in colour. [NCERT Exemplar]

Answer

Answer: a


36. In a Young’s double slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case
(a) there shall be alternate interference patterns of red and blue.
(b) there shall be an interference pattern for red distinct from that for blue.
(c) there shall be no interference fringes.
(d) there shall be an interference pattern for red mixing with one for blue. [NCERT Exemplar]

Answer

Answer: c


37. Figure shows a standard two slit arrangement with slits S1 S2. P1 P2 are the two minima points on either side of P (Figure). At P2 on the screen, there is a hole and behind P2 is a second 2- slit arrangement with slits S3, S4 and a second screen behind them. [NCERT Exemplar]
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 7
(a) There would be no interference pattern on the second screen but it would be lighted.
(b) The second screen would be totally dark.
(c) There would be a single bright point on the second screen.
(d) There would be a regular two slit pattern on the second screen.

Answer

Answer: d


38. Consider the diffraction pattern for a small pinhole. As the size of the hole is increased
(a) the size decreases.
(b) the intensity decreases.
(c) the size increases.
(d) the intensity decreases. [NCERT Exemplar]

Answer

Answer: a


39. For light diverging from a point source
(a) the wavefront is spherical.
(b) the intensity increases in proportion to the distance squared.
(c) the wavefront is parabolic.
(d) the intensity at the wavefront does not depend on the distance.

Answer

Answer: a


40. A continuous locus of particles of medium vibrating in the same phase at any instant is known as _______ .

Answer/Explanation

Answer:
Explaination: wavefront


41. Superposition of two waves in the same phase ‘ to produce maximum intensity is known as _______ interference.

Answer/Explanation

Answer:
Explaination: constructive


42. Phenomenon of bending of light around comers of a small obstacle and spreading into region of geometrical shadow is called _______ of light.

Answer/Explanation

Answer:
Explaination: diffraction


43. Resolving power of an optical instrument is _______ to limit resolution.

Answer/Explanation

Answer:
Explaination: reciprocal


44. Plane of polarisation is _______ to plane of vibration.

Answer/Explanation

Answer:
Explaination: perpendicular


45. For a destructive interference, phase difference between wave is _______ .

Answer/Explanation

Answer:
Explaination: (2n – 1)π


46. Path difference between two waves, having wavelength X and undergoing constructive interference is _______ .

Answer/Explanation

Answer:
Explaination: nλ


47. What is a phase difference between two points on the same wavefront?

Answer/Explanation

Answer:
Explaination: Zero.


48. Sketch the shape of wavefront emerging from a point source of light and also mark the rays.

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 14


49. What type of wavefront will emerge from a
(i) point source, and
(ii) distant light source?

Answer/Explanation

Answer:
Explaination:
(i) Point source — Spherical wavefront.
(ii) Distant light source—Plane wavefront.


50. Draw the wavefront coming out of a convex lens when a point source of light is placed at its focus.

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 15


51. Draw the wavefront, if a point source is placed at point 2F of a convex lens.

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 16


52. When monochromatic light travels from one medium to another its wavelength changes but frequency remains the same. Explain. [NCERT Example, Delhi 2011]

Answer/Explanation

Answer:
Explaination:
When a monochromatic light is incident on the surface separating two media, the atoms of the media interact with the light and may be viewed as oscillators, which take up the frequency of light causing forced oscillations.
Thus, the frequency remains same. But in medium, the speed changes, and accordingly the wavelength changes.


53. When light travels from a rarer to a denser medium, the speed decreases. Does the reduction in speed imply a reduction in the energy carried by the light wave?

Answer/Explanation

Answer:
Explaination: No, as energy ∝ (amplitude)² and is independent of speed of wave.


54. What is meant by interference of light?

Answer/Explanation

Answer:
Explaination:
The phenomenon of non-uniform distribution of energy in a medium due to the superposition of two light waves from two coherent sources is called interference of light.


55. The interference fringe pattern according to the theory is hyperbola. What is the condition for seeing nearly straight fringes?

Answer/Explanation

Answer:
Explaination:
If distance between the plane of the two coherent sources and screen is very large compared to the fringe width; the fringes will be nearly straight lines.


56. Why are coherent sources required to create interference of light?

Answer/Explanation

Answer:
Explaination:
Without coherent sources, the intensity of the interference pattern will not be sustained.


57. State the reason, why two independent sources of light cannot be considered as coherent sources.

Answer/Explanation

Answer:
Explaination: They cannot keep a constant phase difference.


58. In the wave picture of light, intensity of light is determined by the square of the amplitude of the wave. What determines the intensity of light in the photon picture of light. [NCERT Example]

Answer/Explanation

Answer:
Explaination:
In photon picture, the intensity is determined as
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 17


59. What is the effect on the interference fringes in a Young’s double slit experiment if the screen is moved away from the plane of the slits?

Answer/Explanation

Answer:
Explaination:
The angular separation of the fringes remains constant (=λ/d). The actual linear separation of the fringes increases in proportion to the distance of the screen from the plane of the two slits.


60. What is the ratio of the fringe width for bright and dark fringes in Young’s double slit experiment? [HOTS]

Answer/Explanation

Answer:
Explaination: 1 : 1


61. How many interference fringes will be seenthe separation if the size of each slit is \(\left(\frac{1}{5}\right)^{th}\) the separation between the two slits?

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 18


62. How does the fringe width, in Young’s double slit experiment, change when the distance of separation between the slits and screen is doubled? [AI2012]

Answer/Explanation

Answer:
Explaination:
\(\beta=\frac{\lambda D}{d}\) As β ∝ D, when the distance between the slits and the screen is doubled.
The fringe width will also get doubled.


63. When a monochromatic source is replaced by a source of white light in Young’s double-slit experiment, then which colour will appear closest to the central white fringe.

Answer/Explanation

Answer:
Explaination:
The fringe closest on either side of the central white fringe is red.
Explaination: For a point P for which S2P – S1P = \(\frac{\lambda_{b}}{2}\)
where λb represents wavelength for blud colour, the blue component will be absent and red colour fringe will appear. [λb < λR]


64. What is the effect on the interference fringes in a Young’s double slit experiment, if the width of the source slit is increased? [NCERT Example]

Answer/Explanation

Answer:
Explaination:
As the source slit width increases, the fringe pattern gets less and less sharp. When the source slit is so wide that the condition s/S ≤ λ/d is not satisfied, the interference pattern disappears.


65. One of the two slits in Young’s double slit experiment is so painted that it transmits half the intensity of the other. What is the effect on interference fringes? [HOTS]

Answer/Explanation

Answer:
Explaination: The contrast between the bright and dark fringes decreases.


66. Why does the intensity of the secondary maximum become less as compared to the central maximum?

Answer/Explanation

Answer:
Explaination:
As the order increases only \(\frac{1}{n^{\mathrm{th}}}\) (where n is an odd number) of the slit will contribute in producing brightness at a point in the diffraction. So, the higher order maxima are not so bright as the central.


67. How does the angular separation of interference fringes change, in Young’s experiment, if the distance between the slits is increased?

Answer/Explanation

Answer:
Explaination: Decreases, as θ = \(\frac{\lambda}{d}\)


68. What is the condition that only interference is observed in double slit experiment, diffraction is not?

Answer/Explanation

Answer:
Explaination:
When \(\frac{a}{d}\) << 1 then the diffraction pattern will become very flat and we observe only the interference pattern.


69. How are interference and diffraction consistent with the principle of conservation of energy?

Answer/Explanation

Answer:
Explaination:
In interference and diffraction, the light energy is redistributed. If it reduces in one region, producing a dark fringe, it increases in another region, producing a bright fringe. There is no gain or loss of energy, and the two phenomena are consistent with the principle of conservation of energy.


70. Why does the bluish colour predominate in a clear sky?

Answer/Explanation

Answer:
Explaination:
Our eyes are more sensitive to blue colour.


71. An unpolarised light of intensity 1 is passed through a polaroid. What is the intensity of the light transmitted by the polaroid?

Answer/Explanation

Answer:
Explaination:
\(\frac{I}{2}\) as it will get polarised.


72. If the angle between the axis of polariser and the analyser is 45°, write the ratio of the intensities of original light and the transmitted light after passing through the analyser.

Answer/Explanation

Answer:
Explaination:
As I = \(\frac{I_{0}}{2}\) cos² θ, where I0 is the original intensity and 0 is the angle between the axis of the polariser and the analyser.
Physics MCQs for Class 12 with Answers Chapter 10 Wave Optics 19


73. Does the value of polarising angle depend on the colour of light?

Answer/Explanation

Answer:
Explaination: Yes, as μ = tan ip and μ ∝ \(\frac{1}{\lambda^{2}}\)


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Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments

Free PDF Download of CBSE Physics Multiple Choice Questions for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments. Physics MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Physics Ray Optics and Optical Instruments MCQs Pdf with Answers to know their preparation level.

Ray Optics and Optical Instruments Class 12 Physics MCQs Pdf

MCQ on ray optics class 12 Question 1. A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen.
(a) half the image will disappear.
(b) incomplete image will be formed.
(c) intensity of image will decrease but complete image is formed.
(d) intensity of image will increase but image is not distinct.

Answer/Explanation

Answer: c
Explaination:
(c) because focal length of lens does not change but amount of light passing through lens becomes half.


2. In optical fibres, the refractive index of the core is
(a) greater than that of the cladding.
(b) equal to that of the cladding.
(c) smaller than that of the cladding.
(d) independent of that of cladding.

Answer/Explanation

Answer: a
Explaination:
(a) R.I. of core is greater than that of the cladding for total internal reflection to occur.


Ray optics MCQ Questions pdf Question 3. An object is placed at a distance of 0.5 m in front of a plane mirror. The distance between object and image will be
(a) 0.25 m
(b) 0.5 m
(c) 1.0 m
(d) 2.0 m

Answer/Explanation

Answer: c
Explaination:
(c) Distance between object and image = 0.5 + 0.5 = 1.0 m


4. Air bubble in water behaves as
(a) sometimes concave, sometimes convex lens
(b) concave lens
(c) convex lens
(d) always refracting surface

Answer/Explanation

Answer: b
Explaination:
(b) Air bubble in water behaves as a concave lens.


MCQ on ray optics class 12 pdf 5. We combine two lenses, one is convex and other is concave having focal lengths /, and f2 and their combined focal length is F. Combination of the lenses will behave like concave lens, if
(a) f1 > f2
(b) f1 = f2
(c) f1 < f2.
(d) f1 ≤ f2

Answer/Explanation

Answer: a
Explaination:
(a) Focal length of the combination \(F=\frac{f_{1} f_{2}}{f_{1}+f_{2}}\), as f2 is negative so denominator f1 + f2 must be positive or f1 > f2.


Optics Multiple choice Questions and Answers pdf Question 6. The length of an astronomical telescope for normal vision (relaxed eye) will be
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 1

Answer/Explanation

Answer: d
Explaination:
(d) In normal vision, length of telescope L = f0 + fe


Ray optics MCQ Question 7. The focal length of a biconvex lens of radii of each surface 50 cm and refractive index 1.5, is
(a) 40.4 cm
(b) 75 cm
(c) 50 cm
(d) 80 cm

Answer/Explanation

Answer: c
Explaination:
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 6


8. A metal coin is at bottom of a beaker filled with a liquid of refractive index = 4/3 to height of 6 cm. To an observer looking from above the surface of liquid, coin will appear at a depth
(a) 1.5 cm
(b) 6.75 cm
(c) 4.5 cm
(d) 7.5 cm

Answer/Explanation

Answer: c
Explaination:
Ray optics MCQ pdf


9. Tom’ lenses of focal lengths ± 15 cm and ± 150 cm are available for making a telescope. To produce the largest magnification, the focal length of the eyepiece should be
(a) + 15 cm
(b) + 150 cm
(c) – 150 cm
(d) – 15 cm

Answer/Explanation

Answer:
Explaination:
(a) For telescope magnification,
Optics MCQ
to produce large magnification.


10. If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power?
(a) + 6.5 D
(b) – 6.5 D
(c) + 7.5 D
(d) – 0.75 D

Answer/Explanation

Answer:
Explaination:
(d) Focal length of the combination
MCQ on ray optics class 11


Ray optics class 12 Questions and Answers pdf 11. A convex lens and a concave lens, each having the same focal length of 25 cm, are put in contact to form a combination of lenses. The power of the combination (in dioptres) is
(a) zero
(b) 25
(c) 50
(d) infinity

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 10


12. The refractive index of the material of an equilateral prism is √3. What is the angle of minimum deviation?
(a) 45°
(b) 60°
(c) 37°
(d) 30°

Answer/Explanation

Answer:
Explaination:
(b) At minimum deviation position,
Optics Questions and Answers pdf


13. In the formation of a rainbow, the light from the sun on water droplets undergoes
(a) dispersion only.
(b) only TIR.
(c) dispersion and TIR.
(d) scattering.

Answer/Explanation

Answer: b
Explaination:
(b) Rainbow is formed due to dispersion of sunlight by raindrops and total internal reflection inside the raindrop.


14. In an experiment to find focal length of a concave mirror, a graph is drawn between the magnitude of u and v. The graph looks like
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 2

Answer/Explanation

Answer: c
Explaination: (c) u – v curve is a rectangular parabola.


15. A convex lens of refractive index \(\frac{3}{2}\) has a power of 2.5 D in air. If it is placed in a liquid of refractive index 2 then the new power of the lens is
(a) – 1.25 D
(b) – 1.5 D
(c) 1.25 D
(d) 1.5 D

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 12


16. A double convex lens of refractive index µ1 is immersed in a liquid of refractive index µ2. The lens will act as transparent plane sheet when
(a) µ1 = µ2
(b) µ1 > µ2
(c) µ1 < µ2
(d) µ1 = \(\frac{1}{\mu_{2}}\)

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 13


17. When a ray of light enters from one medium to another, then which of the following does not change?
(a) Frequency
(b) Wavelength
(c) Speed
(d) Amplitude

Answer/Explanation

Answer: a
Explaination:
(a) Only frequency of ray of light does not change when it propagates from one medium to another.


18. A diver at a depth 12 m inside water (p = 4/3) sees the sky in a cone of semi-vertical angle
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 5

Answer/Explanation

Answer: c
Explaination:
(c) Required semi vertical angle = Critical angle ic
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 14


19. The astronomical telescope consists of objective and eyepiece. The focal length of the objective is
(a) equal to that of the eyepiece.
(b) shorter than that of eyepiece.
(c) greater than that of eyepiece.
(d) five times shorter than that of eyepiece.

Answer/Explanation

Answer: c
Explaination: (c) For producing large magnification focal length of objective is greater than that of the eyepiece.


20. A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 ’em in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is
(a) 10 cm
(b) 15 cm
(c) 2.5 cm
(d) 5 cm

Answer

Answer: d


21. For a total internal reflection, which of the following is correct?
(a) Light travels from rarer to denser medium.
(b) Light travels from denser to rarer medium.
(c) Light travels in air only.
(d) Light travels in water only.

Answer

Answer: b


22. Critical angle of glass is θ2 and that of water is θ2. The critical angle for water and glass surface would be (μg = 3/2, μw = 4/3).
(a) less than θ2
(b) between θ1 and θ2
(c) greater than θ2
(d) less than θ1

Answer

Answer: c


23. Mirage is a phenomenon due to
(a) refraction of light
(b) reflection of light
(c) total internal reflection of light
(d) diffraction of light.

Answer

Answer: c


24. A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will
(a) become zero
(b) become infinite
(c) become small, but non-zero
(d) remain unchanged

Answer

Answer: b


25. Which of the following forms a virtual and erect image for all positions of the object?
(a) Concave lens
(b) Concave mirror
(d) Convex mirror
(d) Both (a) and (c)

Answer

Answer: d


26. Two lenses of focal lengths 20 cm and – 40 cm are held in contact. The image of an object at infinity will be formed by the combination at
(a) 10 cm
(b) 20 cm
(c) 40 cm
(d) infinity

Answer

Answer: c


27. Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be
(a) 30° for both the colors
(b) greater for the violet color
(c) greater for the red color
(d) equal but not 30° for both the colors

Answer

Answer: a


28. Which of the following colours of white light deviated most when passes through a prism?
(a) Red light
(b) Violet light
(c) Yellow light
(d) Both (a) and (b)

Answer

Answer: b


29. An under-water swimmer cannot see very clearly even in absolutely clear water because of
(a) absorption of light in water
(b) scattering of light in water
(c) reduction of speed of light in water
(d) change in the focal length of eye lens

Answer

Answer: d


30. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Then
(a) the magnification is 1000
(b) the length of the telescope tube is 20.02 m
(c) the image formed of inverted
(d) all of these

Answer

Answer: d


31. An object is immersed in a fluid. In order that the object becomes invisible, it should
(a) behave as a perfect reflector.
(b) absorb all light falling on it.
(c) have refractive index one.
(d) have refractive index exactly matching with that of the surrounding fluid.

Answer

Answer: d


32. A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5° and the prism is made of a material of refractive index 1.5, the angle of incidence is [NCERT Exemplar]
(a) 7.5°
(b) 5°
(c) 15°
(d) 2.5°

Answer

Answer: a


33. A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is [NCERT Exemplar]
(a) blue
(b) green
(c) violet
(d) red

Answer

Answer: d


34. An object approaches a convergent lens from the left of the lens with a uniform speed 5 m/s and stops at the focus. The image [NCERT Exemplar]
(a) moves away from the lens with an uniform speed 5 m/s.
(b) moves away from the lens with an uniform accleration.
(c) moves away from the lens with a non-uniform acceleration.
(d) moves towards the lens with a non-uniform acceleration.

Answer

Answer: c


35. You are given four sources of light each one providing a light of a single colour – red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is 90°. Which of the following statements is correct if the source of yellow light is replaced with that of other lights without changing the angle of incidence? [NCERT Exemplar]
(a) The beam of red light would undergo total internal reflection.
(b) The beam of red light would bend towards normal while it gets refracted through the second medium.
(c) The beam of blue light would undergo total internal reflection.
(d) The beam of green light would bend away from the normal as it gets refracted through the second medium.

Answer

Answer: c


36. The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it will [NCERT Exemplar]
(a) act as a convex lens only for the objects that lie on its curved side.
(b) act as a concave lens for the objects that lie on its curved side.
(c) act as a convex lens irrespective of the side on which the object lies.
(d) act as a concave lens irrespective of side on which the object lies.

Answer

Answer: c


37. The direction of ray of light incident on a concave mirror is shown by PQ while directions in which the ray would travel after reflection is shown by four rays marked 1, 2, 3 and 4. Which of the four rays correctly shows the direction of reflected ray? [NCERT Exemplar]
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 3
(a) 1
(b) 2
(c) 3
(d) 4

Answer

Answer: b


38. The optical density of turpentine is higher than that of water while its mass density is lower. Figure shows a layer of turpentine floating over water in a container. For which one of the four rays incident on turpentine in figure the path shown is correct? [NCERT Exemplar]
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 4
(a) 1
(b) 2
(c) 3
(d) 4

Answer

Answer: b


39. A car is moving with at a constant speed of 60 km h-1 on a straight road. Looking at the rear view mirror, the driver finds that the car following him is at a distance of 100 m and is approaching with a speed of 5 km h-1. In order to keep track of the car in the rear, the driver begins to glance alternatively at the rear and side mirror of his car after every 2 s till the other car overtakes. If the two cars were maintaining their speeds, which of the following statement (s) is/are correct? [NCERT Exemplar]
(a) The speed of the car in the rear is 65 km h-1.
(b) In the side mirror the car in the rear would appear to approach with a speed of 5 km h-1 to the driver of the leading car.
(c) In the rear view mirror the speed of the approaching car would appear to decrease as the distance between the cars decreases.
(d) In the side mirror, the speed of the approaching car would appear to increase as the distance between the cars decreases.

Answer

Answer: d


40. Consider an extended object immersed in water contained in a plane trough. When seen from close to the edge of the trough the object looks distorted. Which of the following is not correct.
(a) the apparent depth of the points close to the edge are nearer the surface of the water compared to the points away from the edge.
(b) the angle subtended by the image of the object at the eye is smaller than the actual angle subtended by the object in air.
(c) some of the points of the object far away from the edge may not be visible because of total internal reflection.
(d) water in a trough acts as a lens and magnifies the object.

Answer

Answer: d


41. A magnifying glass is used, as the object to be viewed can be brought closer to the eye than the normal near point. This results in
(a) a larger angle to be subtended by the object at the eye and hence viewed in greater detail.
(b) the formation of a real inverted image.
(c) increase in the field of view.
(d) infinite magnification at the near point.

Answer

Answer: a


42. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Which one of the following is not correct?
(a) The length of the telescope tube is 20.02 m.
(b) The magnification is 1000.
(c) The image formed is inverted.
(d) An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image.

Answer

Answer: d


43. Virtual image formed by convex mirror has magnification _________ .

Answer/Explanation

Answer:
Explaination: negative


44. Optical denseness of a medium is measured in terms of _________ .

Answer/Explanation

Answer:
Explaination: refractive index


45. Minimum angle of incidence in the denser medium for which angle of refraction becomes 90° is called _________ .

Answer/Explanation

Answer:
Explaination: critical angle


46. Relation between critical angle and refractive index is _________ .

Answer/Explanation

Answer:
Explaination: \(\mu=\frac{1}{\sin i_{c}}\)


47. Optical fibre works on the principle of

Answer/Explanation

Answer:
Explaination: Total internal reflection


48. The splitting of white light into its constituent colours when it passes through a glass prism is called _________ .

Answer/Explanation

Answer:
Explaination: dispersion


49. Blue colour of sky is due to phenomenon of _________ of sunlight.

Answer/Explanation

Answer:
Explaination: scattering


50. A ray of monochromatic light passes from medium (1) to medium (2). If the angle of incidence in medium (1) is θ and the corresponding angle of refraction in medium (2) is θ/2, which of the two media is optically denser? Give reason. [Foreign 2013]

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 15


51. For the same value of angle of incidence, the angles of refraction in three media A, B and C are 15°, 25° and 35° respectively. In which medium would the velocity of light be minimum? [AI2012]

Answer/Explanation

Answer:
Explaination:
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 16
Thus, the medium for which angle of refraction is of 15°, the speed of light is minimum.


52. A concave lens of refractive index 1.5 is immersed in a medium of refractive index 1.65. What is the nature of the lens? [Delhi 2015]

Answer/Explanation

Answer:
Explaination: The nature of the lens is converging.


53. A lens behaves as a converging lens in air and a diverging lens in water (μ = 4/3). What will be the condition on the value of refractive index (μ) of the material of the lens? [Delhi 2011C]

Answer/Explanation

Answer:
Explaination:
The refractive index p of the lens is less than the refractive index of water, i.e. \(\frac{4}{3}\) > μL > 1.


54. An air bubble is formed inside water. Does it act as a converging lens or a diverging lens? [DoE]

Answer/Explanation

Answer:
Explaination: An air bubble behaves as a diverging lens inside the water.


55. The image of an object formed by a lens on the screen is not in sharp focus. Suggest a method to get the clear focussing of the image on the screen without disturbing the position of the object, the lens or the screen.

Answer/Explanation

Answer:
Explaination:
The image of an object formed by a lens can be brought to a sharp focus on a unfixed screen by changing the focal length of the lens by any of the following methods:
(i) By placing another lens of suitable focal length in contact with the previous lens.
(ii) By immersing the given lens in a liquid of appropriate refractive index.


56. Can absolute value of refractive index of a medium be less than unity?

Answer/Explanation

Answer:
Explaination:
As the speed of light is maximum in vacuum, therefore absolute value of refractive index cannot be less than unity as it is given by the relation n = \(\frac{c}{v}\).


57. For which material the value of refractive index is (i) minimum and (ii) maximum?

Answer/Explanation

Answer:
Explaination:
(i) Refractive index is minimum for vacuum (μ = 1).
(ii) Refractive index is maximum for diamond.


58. Can virtual image be photographed?

Answer/Explanation

Answer:
Explaination:
Yes, because the lens in the camera produces a real image of the virtual image being formed.


59. How does the angle of minimum deviation of a glass prism vary, if the incident violet light is replaced with red light? [Chennai 2019, AI 2017]

Answer/Explanation

Answer:
Explaination: It decreases.


60. An object is first seen in red light and then in violet light through a simple microscope. In which case is the magnifying power larger?

Answer/Explanation

Answer:
Explaination:
As we know m = 1 + \(\frac{D}{f}\)
∵ fV < fR
So, the magnifying power is larger when the object is seen in violet light.


61. Name the phenomenon due to which one cannot see through the fog. [DoE]

Answer/Explanation

Answer:
Explaination: Due to scattering of light, one cannot see through the fog.


62. How does the angle of minimum deviation of a glass prism of refractive index 1.5 change, if it is immersed in a liquid of refractive index 1.3?

Answer/Explanation

Answer:
Explaination: It will decrease.


63. A convex lens is placed in contact with a plane mirror. A point object at a distance of 20 cm on the axis of this combination has its image coinciding with itself. What is the focal length of the lens? [Delhi 2014]

Answer/Explanation

Answer:
Explaination: The focal length of convex lens is 20 cm.


64. If an object is moved from infinity to convex mirror, then in which direction will the image shift?

Answer/Explanation

Answer:
Explaination: The image will shift from focus to the convex mirror.


65. A green light is incident from water to the air-water interface at the critical angle (θ). Which part of the spectrum will come out in the air medium?

Answer/Explanation

Answer:
Explaination: The spectrum of visible light whose frequency is less than that of green light will come out of the water into the air.


66. How do the increasing (i) wavelength and (ii) intensity of light affect the speed of light in glass?

Answer/Explanation

Answer:
Explaination:
(i) ∵ v ∝ λ; ∴ speed of light increases on increasing the wavelength in glass.
(ii) There is no effect on speed of light on changing the intensity.


67. Name the principle on which an optical fibre works.

Answer/Explanation

Answer:
Explaination: Total internal reflection.


68. Why is there no dispersion in the light refracted through a rectangular glass slab?

Answer/Explanation

Answer:
Explaination:
A glass slab can be considered as two glass prisms placed together and the position of one prism is inverted w.r.t. another. Therefore, the various colours of white light dispersed by the first prism are again combined to form white light.


69. The line AB in the ray diagram represents a lens. State whether the lens is convex or concave.

Answer/Explanation

Answer:
Explaination:
It is a diverging (concave lens) and the refracted rays are bending away from the principal axis.
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 17


70. A ray of light incident on one of the faces of a glass prism of angle A has angle of incidence 2A. The refracted ray in the prism strikes the opposite face which is silvered, the reflected ray from it retracing its path. Trace the ray diagram and find the relation between the refractive index of the material of the prism and the angle of the prism.

Answer/Explanation

Answer:
Explaination:
Given: i = 2 A, r = 90° – (90° – A) = A
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 18
∴ n = 2 cos A


71. Does the magnifying power of a microscope depend on the colour of the light used? Justify your answer. [Foreign 2017]

Answer/Explanation

Answer:
Explaination:
Magnifying power of a microscope,
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 19
Since the focal length of a convex lens depends on the refractive index, and refractive indices for different colours are different, so according to the lens maker’s formula
Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments 20
The magnifying power of a microscope depends on the colour of the light used.


We hope the given Physics MCQs for Class 12 with Answers Chapter 9 Ray Optics and Optical Instruments will help you. If you have any query regarding CBSE Class 12 Physics Ray Optics and Optical Instruments MCQs Pdf, drop a comment below and we will get back to you at the earliest.

Maths MCQs for Class 12 with Answers Chapter 13 Probability

Free PDF Download of CBSE Maths Multiple Choice Questions for Class 12 with Answers Chapter 13 Probability. Maths MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Maths Probability MCQs Pdf with Answers to know their preparation level.

Probability Class 12 Maths MCQs Pdf

1. Let A and B be two given events such that P(A) = 0.6, P(B) = 0.2 and P(A/B) = 0.5. Then P(A’/B’) is
Maths MCQs for Class 12 with Answers Chapter 13 Probability 1

Answer/Explanation

Answer: c
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 4


2. Let A and B be two given independent events such that P(A) =p and P(B) = q and P(exactly one of A, B) = \(\frac{2}{3}\), then value of 3p + 3q – 6pq is
(a) 2
(b) -2
(c) 4
(d) -4

Answer/Explanation

Answer: a
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 6
Maths MCQs for Class 12 with Answers Chapter 13 Probability 7


3. If P(A ∩ B) = 70% and P(B) = 85%, then P(A/B) is equal to
Maths MCQs for Class 12 with Answers Chapter 13 Probability 2

Answer/Explanation

Answer: a
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 8


4. Two dice are thrown once. If it is known that the sum of the numbers on the dice was less than 6 the probability of getting a sum 3 is
Maths MCQs for Class 12 with Answers Chapter 13 Probability 3

Answer/Explanation

Answer: c
Explaination: (c), as favourable cases for sum less than 6 are 10 and favourable for a total of 3 is 2.


5. Three balls are drawn from a bag containing 2 red and 5 black balls, if the random variable X represents the number of red balls drawn, then X can take values
(a) 0, 1, 2
(b) 0, 1, 2, 3
(c) 0
(d) 1, 2

Answer/Explanation

Answer: a
Explaination: (a), as there are 2 red balls, so maximum ’ red balls can be 2.


6. The probability distribution of the discrete variable X is given as:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 24
The value of k is
(a) 8
(b) 16
(c) 32
(d) 48

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 19


7. Let A and B be two given mutually exclusive events. Then P(A/B) is _________ .

Answer/Explanation

Answer:
Explaination: 0, as P(A ∩ B) = 0 and P(A/B) = \(\frac{P(A \cap B)}{P(B)}\)


8. If A and B are two independent events such that P(A) = \(\frac{1}{7}\) and P(B) = \(\frac{1}{6}\) then P(A’ ∩ B’) is _________ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 5


9. Three persons A, B and C, fire a target in turn. Their probabilities of hitting the target are 0.2,0.3 and 0.5 respectively, the probability that target hit is _________ .

Answer/Explanation

Answer:
Explaination:
0.72, as /^target hit)
= P(at least one hits the target)
= 1 – P( none hits) =1 \(-P(\bar{A} \bar{B} \bar{C})\)


10. If A and B are independent events, then P(A and B) = P(A) + P(B). State true or false.

Answer/Explanation

Answer:
Explaination: False, as P(A and B) = P(A) P(B).


11. A speaks truth in 70% cases and B speaks truth in 85% cases. The probability that they speak the same fact is ______ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 9


12. Given P(A) = 0.4, P(B) = 0.7 and P(B/A) = 0.6. Find P(A ∪ B).

Answer/Explanation

Answer:
Explaination: .
P(B/A) = \(\frac{P(A \cap B)}{P(A)}\)
⇒ 0.6 × 0.4 = P (A ∩ B)
⇒ P(A ∩ B) = 0.24
Now, P(A ∪ B) = P(A) + P(B) – P(A ∩ B)
= 0.4 + 0.7 – 0.24
= 0.86


13. Given P(A) = \(\frac{1}{2}\) p(B) = \(\frac{1}{3}\) and P(A ∩ B) = \(\frac{1}{6}\). Are the events A and B independent?

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 10


14. Prove that if E and F are independent events, then the events E and F are also independent. [Delhi 2017]

Answer/Explanation

Answer:
Explaination:
As E and F are independent events
∴ P(E ∩ F) = P(E)P(F) …(i)
Consider,
P(E)P(F) = P(E)[1 – P(F)]
= P(E) – P(E)P(F)
= P(E) – P(E ∩ F)
P(E)P(F’) = P(E ∩ F’)
⇒ E and F’ are independent events.


15. A die, whose faces are marked 1, 2, 3 in red and 4,5,6 in green, is tossed. Let A be the event “number obtained is even” and B be the event “number obtained is red”. Find if A and B are independent events. [AI 2017]

Answer/Explanation

Answer:
Explaination:
A : number is even, i.e. 2, 4, 6; P(A) = \(\frac{3}{6}\)
= \(\frac{1}{2}\)
B : number is red, i.e. 1, 2, 3; P(B) = \(\frac{3}{6}\)
= \(\frac{1}{2}\)
A ∩ B : number is even and red, i.e. 2;
P(A ∩ B) = \(\frac{1}{6}\)
P(A) × P(B) = \(\frac{1}{2} \times \frac{1}{2}=\frac{1}{4}\)
As P(A ∩ B) ≠ P(A) . P(B)
Hence, not independent.


16. A black and a red die are rolled together. Find the conditional probability of obtaining the sum 8, given that the red die resulted in a number less than 4. [CBSE 2018]

Answer/Explanation

Answer:
Explaination:
A : sum 8, i.e. (2, 6), (3, 5), (4, 4), (5, 3), (6, 2)
B : red die number less than 4.
B : (1, 1), (2, 1), (3, 1), (4, 1), (5, 1), (6, 1), (1, 2), (2, 2), (3, 2), (4, 2), (5, 2), (6, 2), (1, 3), (2, 3), (3, 3), (4, 3), (5, 3), (6, 3).
A ∩ B : (6, 2), (5, 3)
∴ Conditional probability of obtaining sum 8, given that red die resulted in number less than 4.
Maths MCQs for Class 12 with Answers Chapter 13 Probability 11


17. 12 cards numbered 1 to 12 are placed in a box, mixed up thoroughly and then a card is drawn at random from the box. If it is known that the number on the drawn card is more than 3, find the probability that it is an even number.

Answer/Explanation

Answer:
Explaination:
Total cards are 12
A : number drawn is more than 3, i.e. 4, 5, 6, …, 12.
B : getting an even number, i.e. 2, 4, 6, 8, 10, 12.
A ∩ B : 4, 6, 8, 10, 12
Maths MCQs for Class 12 with Answers Chapter 13 Probability 12


18. One card is drawn from a well shuffled pack of 52 cards. If E is the event “the card drawn is a king or a queen” and F is the event “the card drawn is an ace or a queen,” then find the probability of the conditional event E/F. [HOTS]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 13


19. Two cards are drawn from a well shuffled pack of 52 cards one after the other without replacement. Find the probability that one of them is a queen and the other is a king of opposite colour.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 14


20. A coin is tossed thrice and all eight outcomes are assumed equally likely. Let the event E be “the first throw results in head” and event F be “the last throw results in tail”. Find whether events E and F are independent.

Answer/Explanation

Answer:
Explaination:
Sample space
S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}
E: first throw results in head = {HHH,HHT,HTH,HTT}
F: Last throw result in tail = {HHT, HTT, THT, TTT}
Maths MCQs for Class 12 with Answers Chapter 13 Probability 15


21. Two dice are thrown. Find the probability that the numbers appeared have a sum 8 if it is known that the second die always exhibits 4. [HOTS]

Answer/Explanation

Answer:
Explaination:
A: Sum of the numbers is 8, i.e. {(2,6), (3,5), (4,4), (5,3), (6,2)}
B: the second die always exhibits 4, i.e. {(1,4), (2,4), (3,4), (4,4), (5,4), (6,4)} A ∩ B= {(4, 4)}
Required probability,
Maths MCQs for Class 12 with Answers Chapter 13 Probability 16


22. If P(A)=0.8,P(B)=0.5 andP(B/A)=0.4, find (i) P(A ∩ B) (ii) P(A/B) (iii) P(A ∪ B). [NCERT]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 17


23. The value of k, for which the following distribution is a probability distribution
Maths MCQs for Class 12 with Answers Chapter 13 Probability 23

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 18


24. Find mean (µ) and variance (a2) for the following probability distribution:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 25

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 20
Maths MCQs for Class 12 with Answers Chapter 13 Probability 21


25. A random variable X has a probability distribution P(X) of the following form where k is some number:Determine (i) k (ii) P(X ≤ 2) (iii) P(X ≤ 2) (iv) P(X ≥ 2). [NCERT; Delhi 2019]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 13 Probability 22


We hope the given Maths MCQs for Class 12 with Answers Chapter 13 Probability will help you. If you have any query regarding CBSE Class 12 Maths Probability MCQs Pdf, drop a comment below and we will get back to you at the earliest.

Maths MCQs for Class 12 with Answers Chapter 12 Linear Programming

Free PDF Download of CBSE Maths Multiple Choice Questions for Class 12 with Answers Chapter 12 Linear Programming. Maths MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Maths Linear Programming MCQs Pdf with Answers to know their preparation level.

Linear Programming Class 12 Maths MCQs Pdf

1. Of all the points of the feasible region, for maximum or minimum of objective function, the point lies
(a) inside the feasible region
(b) at the boundary line of the feasible region
(c) vertex point of the boundary of the feasible region
(d) none of these

Answer

Answer: c


2. A dealer wishes to purchase a number of fans and sewing machines. He has only ₹ 5,760 to invest and has space for at most 20 items. A fan costs him ₹ 360 and a sewing machine ₹ 240. He expects to sell a fan at a profit of ₹ 22 and a sewing machine at a profit of ₹ 18. Assinning that he can sell all the items that he buys, how should he invests his money to maximise the profit? The LPP for above question is
(a) x → fans, y → sewing machines
To maximise Z = 22x + 18y
subject to constraints
x ≥ 0, y ≥ 0, x + y ≤ 20
360x + 240y ≥ 5760
(b) x → fans, y → sewing machines
To maximise Z= 18x + 22y subject to constraints
x ≥ 0, y ≥ 0, x + y ≤ 20 360x + 240y ≥ 5760
(c) x → fans, y → sewing machines
To maximise Z = 22x + 18y
x ≥ 0, y ≥ 0, x + y ≥ 0
360x + 240y ≥ 5760
(d) x → fans, y → sewing machines
To maximise Z = 22x + 18j
x ≥ 0, y ≥ 0, x + y ≤ 20 360x + 240y ≤ 5760

Answer

Answer: d


3. Feasible region is the set of points which satisfy
(a) the objective functions
(b) some of the given constraints
(c) all of the given constraints
(d) none of these

Answer

Answer: c


4. An aeroplane can carry a maximum of 200 passangers. A profit of ₹ 400 is made on each first class ticket and a profit of ₹ 300 is made on each economy class ticket. An airline reserves at least 20 seats for first class. However, at least 4 times as many passengers prefer to travel by economy class than by first class. Find how many tickets of each type must be sold to maximise the profit? The LPP for the given situation is
(a) x → first class, y → economy class
To maximise Z = 400x + 300y
subject to constraints
x ≥ 0, y ≥ 0, x+y ≤ 200
x ≥ 20, y ≥ 80
(b) x → first class, y → economy class
To maximise Z 400x + 300y
subject to constraints
x ≥ 0, y ≥ 0, x+y ≥ 200
x ≥ 20, y ≥ 80
(c) x → first class, y → economy class
To maximise Z = 400x + 300y
subject to constraints
x ≥ 0, y ≥ 0, x ≥ 20
x + y ≤ 200
x ≥ 4y
(d) x → first class, y → economy class
To maximise Z = 400x + 300y
subject to constraints
x ≥ 20, y ≥ 0
x + y ≤ 200
y ≥ 4x

Answer

Answer: d


5. A manufacturer makes two types of furniture, chairs and tables. Both the products are processed on three machines A1 A2 and A3. Machine A1 requires 3 hours for a chair and 3 hours for a table, machine A2 requires 5 hours for a chair and 2 hours for a table and machine A3 requires 2 hours for a chair and 6 hours for a table. Maximum time available on machine A1, A2 and A3 is 36 hours, 50 hours and 60 hours respectively. Profits are ₹ 20 per chair and ₹ 30 per table. Formulate the above as a linear programming problem to maximise the profit. [HOTS]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 12 Linear Programming 1
Let x chairs and y tables are manufactured.
Then LPP is Maximise P = 20x + 30y
subject to the constraints, x ≥ 0, y ≥ 0, 3x + 3y ≤ 36, 5x + 2y ≤ 50, 2x + 6y ≤ 60.


6. One kind of cake requires 200 g of flour and 25 g of fat and another kind of cake requires 100 g of flour and 50 g of fat, 5 kg of flour and 1 kg of fat is available, formulate the problem to find the maximum number of cakes which can be made, assuming that there is no shortage of the other ingredients used in making the cakes.

Answer/Explanation

Answer:
Explaination:
Let x cakes of kind I and y cakes of kind II are made.
Then LPP is
Maximise Z = x + y
subject to the constraints x ≥ 0, y ≥ 0
200x + 100y ≤ 5000
25x + 50y ≤ 1000


7. A small firm manufactures necklaces and bracelets. The total number of necklaces and bracelets that it can handle per day is at mo£ 24. It takes one hour to make a bracelet and half an hour to make a necklace. The maximum number of hours available per day is 16. If the profit on a necklace is ₹ 100 and that on a bracelet is ₹ 300. Formulate an LPP for finding how many of each should be produced daily to maximise the profit? It is being given that at lea£ one of each muft be produced. [Delhi 2017]

Answer/Explanation

Answer:
Explaination:
Let x necklaces and y bracelets be produced.
Then LPP is
To maximise profit
Z =100x + 300y
subject to constraints
x ≥ 1, y ≥ 1
x + y ≤ 24; \(\frac{1}{2}\)x + y ≤ 16


8. Two tailors, A and B, earn ₹ 300 and ₹ 400 per day respectively. A can stitch 6 shirts and 4 pairs of trousers while B can stitch 10 shirts and 4 pairs of trousers per day. To find how many days should each of them work and if it is desired to produce at least 60 shirts and 32 pairs of trousers at a minimum labour cost, formulate this as an LPP. [AI 2017]

Answer/Explanation

Answer:
Explaination:
Let A works for x days and B for y days
∴ LPP is to minimise Z = 300x + 400y
subject to the constraints 6x + 10y ≥ 60
4x + 4y ≥ 32
x ≥ 0, y ≥ 0


We hope the given Maths MCQs for Class 12 with Answers Chapter 12 Linear Programming will help you. If you have any query regarding CBSE Class 12 Maths Linear Programming MCQs Pdf, drop a comment below and we will get back to you at the earliest.

Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry

Free PDF Download of CBSE Maths Multiple Choice Questions for Class 12 with Answers Chapter 11 Three Dimensional Geometry. Maths MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Maths Three Dimensional Geometry MCQs Pdf with Answers to know their preparation level.

Three Dimensional Geometry Class 12 Maths MCQs Pdf

1. The distance of point (2, 5, 7) from the x-axis is
(a) 2
(b) √74
(c) √29
(d) √53

Answer/Explanation

Answer: b
Explaination:
(b), as distance of point (2, 5, 7) from the x-axis is
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 12


2. P is a point on the line segment joining the points (3, 5, -1) and (6, 3, -2). If y-coordinate of point P is 2, then its x-coordinate will be
(a) 2
(b) \(\frac{17}{3}\)
(c) \(\frac{15}{2}\)
(d) -5

Answer/Explanation

Answer: c
Explaination:
(c), as let P divides the join of (3, 5, -1) and (6, 3, -2) in the ratio k : 1
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 13


3. Direction ratios of a line are 2, 3, -6. Then direction cosines of a line making obtuse angle with the y-axis are
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 1

Answer/Explanation

Answer: c
Explaination:
(c), as direction cosines of a line whose direction ratio are 2,3, -6 are \(\frac{2}{7}, \frac{3}{7}, \frac{-6}{7}\).
As angle with the y-axis is obtuse,
∴ cos β < 0,
Therefore direction ratios are \(\frac{-2}{7}, \frac{-3}{7}, \frac{6}{7}\).


4. A line makes angle α, β, γ with x-axis, y-axis and z-axis respectively then cos 2α + cos 2β + cos 2γ is equal to
(a) 2
(b) 1
(c) -2
(d) -1

Answer/Explanation

Answer: d
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 14


5. The equations of y-axis in space are
(a) x = 0, y = 0
(b) x = 0, z = 0
(c) y = 0, z = 0
(d) y = 0

Answer/Explanation

Answer: b
Explaination: (b), as on the y-axis, x-coordinate and z-coordinate are zeroes.


6. If the direction cosines of a line are \(\frac{k}{3}, \frac{k}{3}, \frac{k}{3}\), then value of k is
(a) k > 0
(b) 0 < k < 1.
(c) k = \(\frac{1}{3}\)
(d) k = ± 73

Answer/Explanation

Answer: d
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 17


7. Distance of plane \(\vec{r} \cdot(2 \hat{i}+3 \hat{i}-6 \hat{k})+2=0\), from origin is
(a) 2
(b) 14
(c) \(\frac{2}{7}\)
(d) –\(\frac{2}{7}\)

Answer/Explanation

Answer: c
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 31
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 32


8. Distance between planes
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 8
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 9

Answer/Explanation

Answer: c
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 35


9. The line joining the points (0, 5, 4) and (1, 3, 6) meets XY-plane at the point ________ .

Answer/Explanation

Answer:
Explaination:
(-2, 9, 0), as line is \(\frac{x-1}{1}=\frac{y-3}{-2}=\frac{z-6}{2}=\lambda\)
General point on line is (λ + 1, -2λ + 3, 2λ + 6)
If it meets AT-plane, then 2λ + 6 = 0
⇒ λ = – 3
∴ Point is (-2, 9, 0)


10. A line makes angles α, β, γ with z-axis, x-axis and y-axis respectively. Then direction cosines of line are cos β, cos γ, cos α. State true or false.

Answer/Explanation

Answer:
Explaination: True, as direction cosines of a line are cosines of the angles which a line makes with x, y and z-axes respectively.


11. A line makes angles \(\frac{\pi}{4}, \frac{3 \pi}{4}\) with x-axis and y-axis respectively. Then the angle which it makes with z-axis can be ________ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 15


12. The vector equation of the line
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 2
State true or false.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 16


13. The Cartesian equation of a line AB is
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 3
Find the direction cosines of a line parallel to AB.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 18


14. Find the direction cosines of the line passing through the following points: (-2, 4, -5), (1, 2, 3) [NCERT]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 19


15. Find the Cartesian equation of the line which passes through the point (-2,4, -5) and is parallel to the line \(\frac { x+3 }{ 3 } =\frac { 4-y }{ 5 } =\frac { z+8 }{ 6 } \) [Delhi 2013]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 20


16. Write the vector equation of the following line: \(\frac { x-5 }{ 3 } =\frac { y+4 }{ 7 } =\frac { 6-z }{ 2 } \)

Answer/Explanation

Answer:
Explaination:
The line passes through the point (5, -4, 6) and dr’s of the line are 3, 7, – 2.
∴ vector equation is
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 21


17. Write the Cartesian equation of the following line given in vector form:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 4

Answer/Explanation

Answer:
Explaination:
Point through which line passes is (2, 1, -4) and dr’s: 1, – 1, – 1.
∴ Cartesian equation of line
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 22


18. What are the direction cosines of a line, which makes equal angles with the coordinate axes? [NCERT; Foreign 2011]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 23


19. If the direction cosines of a given line are \(\frac{1}{k}, \frac{1}{k}, \frac{1}{k}\) then, find the value of k.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 24


20. If a line makes angles 90° and 60° respectively with the positive directions of x and y axes, find the angle which it makes with the positive direction ofz-axis. [Delhi 2017]

Answer/Explanation

Answer:
Explaination:
Let angle with z-axis be γ.
cos²90° + cos²60° + cos² γ = 1
⇒ 0 + \(\frac{1}{4}\) + cos² γ = 1
⇒ cos² γ = \(\frac{3}{4}\)
cos γ = \(\pm \frac{\sqrt{3}}{2}\)
γ = 30°, 150°


21. Find the vector equation of the line passing through the point A(1, 2,-1) and parallel to the line 5x – 25 = 14 – 7y = 35z. [Delhi 2017]

Answer/Explanation

Answer:
Explaination:
Given line is 5x – 25 = 14 – 7y = 35z
⇒ 5(x – 5) = – 7(y – 2) = 35z
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 25
DR’s of line are 7, – 5 and 1
dr’s of line parallel to the given line are 7,-5, 1.
vector equation of line through the point (1, 2, – 1) and having dr’s 7,-5 and 1 is
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 26


22. Write the distance of the point (3, – 5, 12) from the x-axis. [Foreign 2017]

Answer/Explanation

Answer:
Explaination:
Distance of the point (3, – 5, 12) from the x-axis
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 27


23. Find the angle between the following pair of lines:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 5
and check whether the lines are parallel or perpendicular. [Delhi 2011]

Answer/Explanation

Answer:
Explaination:
DR’s of lines are 2, 7, – 3 and – 1, 2, 4
As 2 × (- 1) + 7 × 2 – 3 × 4 = 0, so lines are perpendicular. Angle = 90°


24. The x-coordinate of a point on the line joining the points P(2, 2, 1) and Q(5, 1, -2) is 4. Find its z-coordinate. [AI2017]

Answer/Explanation

Answer:
Explaination:
Let point R(4, y, z) lies on the line joining P(2, 2, 1) and Q(5, 1, -2). Let R divides PQ in ratio k: 1
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 28


25. If P(1, 5, 4) and Q(4, 1, – 2), find the direction ratios of \(\overrightarrow{P Q}\).

Answer/Explanation

Answer:
Explaination:
Direction ratios of \(\overrightarrow{P Q}\) =4 – 1, 1 – 5 and -2 -4, i.e. 3, -4 and – 6.


26. The equations of a line are 5x – 3 = 15y + 7 = 3 – 10z. Write the direction cosines of the line. [All India]

Answer/Explanation

Answer:
Explaination:
The equation of a line are 5x – 3 = 15y + 7 = -10z + 3
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 29


27. Equation of the perpendicular drawn from the point with position vector \(2 \hat{i}- \hat{j}+ \hat{k}\) to the plane \(\vec{r} \cdot(\hat{i}-3 \hat{k})=5\) is ________ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 30


28. General equation of a plane passing through the intersection of two given
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 6

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 33


29. Cartesian equation of the plane
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 7
State true or false.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 34


30. Find the distance of the point (2,3,4) from the plane
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 10

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 36


31. Write the intercept cut off by the plane 2x + y – z = 5 on the x-axis. [Delhi 2011]

Answer/Explanation

Answer:
Explaination:
For intercept on the x-axis, put y = 0 and z = 0
⇒ 2x = 5
⇒ x = \(\frac{5}{2}\)
∴ x-intercept = \(\frac{5}{2}\)


32. Find the distance of the plane 3x – 4y + 12z = 3 from the origin. [AI 2012]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 37


33. Find the angle between the planes
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 11

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 38


34. Find the distance between the planes 2x – y + 2z – 5 and 5x – 2.5y + 5z = 20. [AI 2017]

Answer/Explanation

Answer:
Explaination:
Planes are 2x – y + 2z = 5
⇒ 2x – y + 2z – 5 = 0
and 5x – 2.5y + 5z = 20
⇒ 2x – y + 2z – 8 = 0
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 39


35. A line passes through the point with position vector \(2 \hat{i}-3 \hat{j}+4 \hat{k}\) and is perpendicular to the plane \(\vec{r} \cdot(3 \hat{i}+4 \hat{j}-5 \hat{k})=7\). Find the

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry 40


We hope the given Maths MCQs for Class 12 with Answers Chapter 11 Three Dimensional Geometry will help you. If you have any query regarding CBSE Class 12 Maths Three Dimensional Geometry MCQs Pdf, drop a comment below and we will get back to you at the earliest.

Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra

Free PDF Download of CBSE Maths Multiple Choice Questions for Class 12 with Answers Chapter 10 Vector Algebra. Maths MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Maths Vector Algebra MCQs Pdf with Answers to know their preparation level.

Vector Algebra Class 12 Maths MCQs Pdf

1. A vector equally inclined to axes is
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 1

Answer/Explanation

Answer: a
Explaination:
(a), as direction ratios are 1, 1, 1 and
direction cosines \(\frac{1}{\sqrt{3}}, \frac{1}{\sqrt{3}}, \frac{1}{\sqrt{3}}\)
⇒ cos α = cos β = cos γ
⇒ α = β = γ


2. The position vector of a point which divides the join of points with position vectors \(\vec{a}+\vec{b}\) and \(2 \vec{a}-\vec{b}\) in the ratio 1:2 internally is
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 2

Answer/Explanation

Answer: d
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 43


3. A vector in the direction of vector \(\hat{i}-2 \hat{j}+2 \hat{k}\) that has magnitude 15 is
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 3

Answer/Explanation

Answer: d
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 45


4. If \(|\vec{a}|\) = 4 and -3 ≤ λ ≤ 2 then the range of \(|\lambda \vec{a}|\) is
(a) [0, 8]
(b) [-12, 8]
(c) [0, 12]
(d) [8, 12]

Answer/Explanation

Answer: c
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 46


5.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 9
(a) 30°
(b) 45°
(c) 60°
(d) 90°

Answer/Explanation

Answer: a
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 59


6.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 27

Answer/Explanation

Answer: c
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 79


7.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 28

Answer/Explanation

Answer: b
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 80


8.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 29

Answer/Explanation

Answer: a
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 81


9. Mathematically a vector is defined as a “directed line segment.” State true or false.

Answer/Explanation

Answer:
Explaination: True


10. If vectors are equal then their magnitudes are equal but the converse may not be true. State true or false.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 42


11. Given vector \(\overrightarrow{P Q}=2 \hat{i}+\hat{j}-3 \hat{k}\) and position vector of point P is \(3 \hat{j}-2 \hat{k}\), then position vector of point Q is _________ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 44


12. Find a unit vector in the direction of \(\overrightarrow{a}=3 \hat{i}-2 \hat{j}+6 \hat{k}\)

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 47


13. For what value of p, is (\(\hat{i}+ \hat{j}- \hat{k}\))p a irnit vector?

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 48


14. If \(\overrightarrow{A B}=2 \hat{i}+\hat{j}-2 \hat{k}\) and \(\overrightarrow{B C}=6 \hat{i}+3\hat{j}-6 \hat{k}\), can we say that the points A, B, C are collinear?

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 49


15. In the given figure, find
(i) parallel or collinear vectors
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 97
(ii) co-initial vectors

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 50


16.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 4

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 51


17.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 5

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 52


18. Find a vector in the direction of \(\vec{a}=\vec{i}-2 \hat{j}\) whose magnitude is 7. [NCERT]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 53


19. For what value of ‘a’ the vectors \(2 \hat{i}-3 \hat{j}+4 \hat{k}\) and \(\hat{a} \hat{i}+\hat{6} \hat{j}-8 \hat{k}\) are collinear?[Delhi2011]

Answer/Explanation

Answer:
Explaination:
For vectors to be collinear \(\frac{2}{a}=\frac{-3}{6}=\frac{4}{-8}\)
⇒ a = -4


20. ABCDEF is a regular hexagon,
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 6

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 54


21. The position vectors A, B, C, D are
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 7

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 55


22. Write the direction cosines of the vector \(-2 \hat{i}+\hat{j}-5 \hat{k}\) [Delhi 2011]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 56


23. Show that the vector \( \hat{i}+\hat{j}+ \hat{k}\) is equally inclined to axes.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 57


24. Write a unit vector in the direction of the
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 8

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 58


25. The value of X for which vectors
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 10
are orthogonal is __________ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 60


26. For any non zero vector \(\vec{a}\),
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 11
State true or false.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 61


27. Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 12
are perpendicular. State true or false.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 62


28. Find the angle between the vectors
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 13

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 63


29.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 14

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 64


30.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 15

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 65


31. If \(\vec{p}\) is a unit vector and
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 16

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 66


32.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 17

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 67


33.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 18

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 68


34. Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 19
\(\vec{b}\) are along adjacent sides of a rectangle.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 69


35.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 20

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 70


36. Find the magnitude of each of the two vectors \(\vec{a}\) and \(\vec{b}\), having the same magnitude such that the angle between them is 60° and their scalar product is \(\frac{9}{2}\). [CBSE 2018]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 71


37.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 21

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 72


38.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 22

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 73


39.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 23

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 74
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 75


40.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 24

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 76


41.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 25

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 77


42.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 26

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 78


43.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 30

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 82


44.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 31

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 83


45.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 32

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 84


46.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 33

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 85


47.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 34

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 86
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 87


48.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 35

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 88


49.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 36

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 89
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 90


50. Write the value of \((\hat{i} \times \hat{j}) . \hat{k}+\hat{i} \hat{j}\) [AI 2012]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 91


51. Write a unit vector perpendicular to both the
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 37 [AI 2015]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 92


52.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 38

Answer/Explanation

Answer:
Explaination: coplanr


53.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 39
(a) 4
(b) 0
(c) -3
(d) 2

Answer/Explanation

Answer: b
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 93


54.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 40

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 94
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 95


55.
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 41

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra 96


We hope the given Maths MCQs for Class 12 with Answers Chapter 10 Vector Algebra will help you. If you have any query regarding CBSE Class 12 Maths Vector Algebra MCQs Pdf, drop a comment below and we will get back to you at the earliest.

Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations

Free PDF Download of CBSE Maths Multiple Choice Questions for Class 12 with Answers Chapter 9 Differential Equations. Maths MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Maths Differential Equations MCQs Pdf with Answers to know their preparation level.

Differential Equations Class 12 Maths MCQs Pdf

1. Order of differential equation correspon- ding to family of curves y = Ae2x + Be2x is ______ .

Answer/Explanation

Answer:
Explaination: 2, as there are two arbitrary constants and we have to differentiate twice.


2. The order of the differential equation corresponding to the family of curves y = c(x – c)², c is constant is ______ .

Answer/Explanation

Answer:
Explaination: One, as there is one arbitrary constant.


3. The degree of differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 1
is not defined. State true or false.

Answer/Explanation

Answer:
Explaination: Three, as equation cannot be represented as polynomial of derivatives.


4. If p and q are the degree and order of the differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 2
then the value of 2p – 3q is
(a) 7
(b) -7
(c) 3
(d) -3

Answer/Explanation

Answer: b
Explaination:
(b), as degree p = 1 and order q = 3
∴ 2p – 3q = 2 – 9 = -7


5. The degree of the differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 3
(a) 1
(b) 2
(c) 3
(d) 4

Answer/Explanation

Answer: c
Explaination:
(c), as differential equation is
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 9
Exponent of highest order derivative is 3.


6. The degree of the differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 4
(a) 1
(b) 2
(c) 3
(d) not defined

Answer/Explanation

Answer: d
Explaination:
(d), as equation cannot be represented as a polynomial of derivatives.


7. The order of the differential equation of all the circles of given radius 4 is
(a) 1
(b)2
(c) 3
(d) 4

Answer/Explanation

Answer: b
Explaination:
(b), as centre is arbitrary (h, k), two arbitrary constants so we have to differentiate twice to eliminate h, k
∴ order is 2.


8. Degree of the differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 5
is not defined. State true or false.

Answer/Explanation

Answer:
Explaination:
False, as equation can be written as
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 10
Further it can be written as a polynomial of derivatives. 9.


9. Write the degree of the differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 6

Answer/Explanation

Answer:
Explaination: Degree 1


10. Write the degree of the differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 7

Answer/Explanation

Answer:
Explaination: Degree 3.


11. Find the value of m and n, where m and n are order and degree of differential equation
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 8

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 11
Order of differential equation (m) = 3
Degree of differential equation (n) = 2


12. Write the order and degree of the differential equation \(\frac{d y}{d x}+\sin \left(\frac{d y}{d x}\right)\) = 0. [HOTS]

Answer/Explanation

Answer:
Explaination:
Highest order derivative is \(\frac{dy}{dx}\). Hence, order of differential equation is 1. Equation cannot be written as a polynomial’ in derivatives. Hence, degree is not defined.


13. The differential equation of the family of lines passing through ongrn is
(a) y = mx
(b) \(\frac{dy}{dx}\) = m
(c) x dy – y dx = 0
(d) \(\frac{dy}{dx}\) = 0

Answer/Explanation

Answer: c
Explaination:
(c), as general equation of line through origin is
y = mx
⇒ \(\frac{dy}{dx}\) = m
Substituting in (i), we get dy
y = \(\frac{dy}{dx}\).x
⇒ x dy – y dx = 0


14. Find the differential equation representing the family of curves y = aebx + 5, where a and b are arbitrary constants. [CBSE 2018]

Answer/Explanation

Answer:
Explaination:
Consider y = aebx + 5
.On differentiating both sides, w.r.t, x
\(\frac{dy}{dx}\) = abebx + 5 = by …..(i)
Again differentiating w.r.t. x, we get
\(\frac{d^{2} y}{d x^{2}}=b \cdot \frac{d y}{d x}\) …..(ii)
From (i) and (ii), eliminating b, we get
\(y \cdot \frac{d^{2} y}{d x^{2}}=\left(\frac{d y}{d x}\right)^{2}\) as required equation.


15. Form the differential equation representing the family of parabolas having vertex at origin and axis along positive direction of the x-axis. [NCERT; DoE]

Answer/Explanation

Answer:
Explaination:
General equation of parabola is y² = 4ax …..(i)
Differentiating, we get 2yy’ = 4a
⇒ yy’ = 2a.
Substituting in (i), we gety2 = 2xyy’.


16. Form the differential equation of the family of parabolas having vertex at the origin and axis along positive y-axis. [Delhi 2011]

Answer/Explanation

Answer:
Explaination:
x² = 4 ay
⇒ 2x = 4 ay’
⇒ \(\frac{x^{2}}{2 x}=\frac{4 a y}{4 a y^{\prime}}\)
⇒ xy’ – 2y = 0 is the required equation.


17. General solution of the differential equation log\(\frac{dy}{dx}\) = 2x +y is _______ .

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 12


18. Solve the differential equation \(\frac{dy}{dx}\) = ex – y + x3e-y.

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 13


19. Find the particular solution of the differential equation \(\frac{dy}{dx}\) =y tanx, given that y= 1 when x = 0.

Answer/Explanation

Answer:
Explaination:
∫ \(\frac{dy}{y}\) = ∫tan x dx
⇒ log |y| = log|sec x| + log C
⇒ y = C sec x ….(i)
Given y = 1, x = 0
⇒ 1 = C sec 0
⇒ C = 1
∴ solution is y = sec x [from (i)]


20. Find the general solution of the differential equation \(\frac{dy}{dx}\) = \(\frac{x+1}{2-y}\), (y ≠ 2). [NCERT]

Answer/Explanation

Answer:
Explaination:
Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations 14


We hope the given Maths MCQs for Class 12 with Answers Chapter 9 Differential Equations will help you. If you have any query regarding CBSE Class 12 Maths Differential Equations MCQs Pdf, drop a comment below and we will get back to you at the earliest.

English Summaries – Poetry, Prose, Fiction, Drama Summary

English Summaries – Poems, Prose, Fiction, Drama Summary

Class 12 English Flamingo

Class 12 English Vistas

Class 11 English Hornbill

Class 11 English Snapshots

Class 10 English First Flight

Class 10 English Footprints Without Feet

Class 10 English Literature Reader

Class 9 English Beehive

Class 9 English Moments

Class 9 English Literature Reader

Class 8 English Honeydew

Class 8 English It So Happened

Class 7 English Honeycomb

Class 7 English An Alien Hand

Class 6 English Honeysuckle

Class 6 English A Pact With the Sun

Treasure Trove Poems Summary

Treasure Trove Short Stories Summary

Summary of Merchant of Venice By William Shakespeare

Call of the Wild Summary

Animal Farm Summary

NCERT Solutions for Class 10 Science Chapter 16 Management of Natural Resources

NCERT Solutions for Class 10 Science Chapter 16 Management of Natural Resources

These Solutions are part of NCERT Solutions for Class 10 Science. Here we have given NCERT Solutions for Class 10 Science Chapter 16 Management of Natural Resources. LearnInsta.com provides you the Free PDF download of NCERT Solutions for Class 10 Science (Biology) Chapter 16 – Management of Natural Resources solved by Expert Teachers as per NCERT (CBSE) Book guidelines. All Chapter 16 – Management of Natural Resources Exercise Questions with Solutions to help you to revise complete Syllabus and Score More marks.

NCERT Questions

In Text Questions

Question 1.
What changes would you make in your habits to become environment friendly ? (CBSE AI 2009)
Answer:
Three Rs — reduce, recycle and reuse.

  1. Reduce: It is to reduce consumption by preventing wastage.
    1. Switching off unnecessary lights, fans and other electrical appliances,
    2. Repair of leaky taps.
    3. Reducing food wastage,
    4. Walking down to nearby market instead of using vehicle.
  2. Recycle: Separation of recyclable wastes from non-recyclable wastes. The former are taken by rag pickers for sending them to industries involved in recycling, e.g., paper, plastic, metal, glass.
  3. Reuse: Carry bags, packing material, plastic containers and other reusable articles should not be thrown away if the same are uncontaminated. For example, plastic bottles and jars containing various food items brought from market can be washed and used for storing things in the kitchen.

More Resources

Question 2.
What would be advantages of exploiting resources with short term aims ?
Answer:

  1. All the commodities for use and comforts for human society will become available in plenty.
  2. There will be rapid industrialisation and development.

Question 3.
How would these advantages differ from the advantages of using a long term prospective in managing our resources ?
Answer:

Short Term Aims

Long Term Aims

1. All the commodities become available in plenty. 1. Availability of various commodities is restricted.
2. There is a tendency to manufacture articles of larger size. 2. There is a tendency to manufacture articles of smaller size.
3. The mentality is of use and throw. 3. The mentality is reuse, recycle and replace.
4. The resources are likely to get exhausted soon. 4. The resources are likely to remain available for a long time.
5. The ecology is disturbed and harmed. 5. It is eco-friendly.

 

Question 4.
Why do you think there should be equitable distribution of resources ? What forces would be working against an equitable distribution of our resources ?
Answer:
Need for Equitable Distribution. Resources are living and non-living components of nature which are drawn upon to provide food, fodder, shelter, water, energy, articles of daily use and comforts. Every human being has the fundamental right to obtain and use the same. This is possible only when there is equitable distribution of resources.
Forces Against Equitable Distribution,

  1. Restricted availability of resources,
  2. Excessive consumption by the rich,
  3. Profit motto by the persons exploiting resources.

Question 5.
Why should we conserve forests and wildlife ?
Answer:
There are economic and ecological reasons to conserve forests and wildlife.

  1. Economic Reasons:
    1. Forests are a source of shelter, food and fodder to people living in and around forests,
    2. They provide firewood and timber,
    3. A number of industrial raw materials are obtained from forests, e.g., tannins, dyes, resins, perfumes, wood for paper,
    4. Several medicines are got from forest plants and animals,
    5. Wildlife is a gene bank for improvement of domesticated plants and animals,
    6. All plants and animals have not yet been explored for their potential uses.
  2. Ecological Reasons:
    1. They regulate climate,
    2. Forests help in retaining rain water and its storage in aquifers from where water becomes available to springs and streams,
    3. Forests control soil erosion and prevent the occurrence of floods,
    4. Wildlife is essential for maintaining the forests.
    5. CO2-O2 balance is maintained.

Question 6.
Suggest some approaches towards the conservation of forests.
Answer:
Conservation is protection, augmentation and scientific management of a resource so as to maintain it at its optimum level while providing sustainable benefits for the present as well as future generations. Some approaches for conservation of forests are as follows :

  1. Afforestation and Reforestation. Afforestation is developing forest over an area where none existed earlier. Reforestation is developing forest cover which has been cleared during exploitation. Degraded forests are also mended to bring them back to health. All this is done by state forest department either by themselves or with the help of joint forest management committees.
  2. Separation of Commercial Forestry. Useful plants required for meeting commercial needs should be planted separately so that there is no undue pressure on natural forests. Social forestry is growing multipurpose plants on village common lands for meeting requirement of fodder, firewood and small timber. Production plantation is growing industry required plants on wastelands.
  3. Controlled grazing.
  4. Prevention of scraping and litter removal.
  5. Practising block cutting or cutting of forest equal to its regeneration capacity.
  6. Building of national parks, sanctuaries and biosphere reserves.

Question 7.
Find out about traditional systems of water harvesting management in your region.
Answer:
Ponds, pools, tanks, lakes, ditches and wetlands. They get filled up during rain. Larger reservoirs are perennial. The smaller ones dry up after a few months. However, both help in recharge of ground water.

Question 8.
Compare the above system with the probable system in hilly/mountainous areas or plains or plateau regions.
Answer:
Hilly/Mountainous Areas. Water is impounded on the slopes, at the base of slope, on the border of ravine or melting snow into tanks called Kulhs, Khatris, Kuls (Himachal Pardesh, J and K), Zabo (Nagaland) and Zings (Ladakh). Water from tanks is used for different purposes—drinking, washing, animals, irrigation.
Plains,

  1. Roof top harvesting of rain water has been in practice since ages in Rajasthan. The collected water is stored below the ground level for later use.
  2. Other methods of water harvesting are specially constructed tanks, Kuis, jhaslars, booris or bers, paar, vivdas, khadins and nadis (Rajasthan), ponds in Kandi belts (Jammu), bhandaras and tals (Maharashtra), bundhis (MP and UP), ahars and pynes (Bihar).
    Plateau. Water is collected in series of tanks through impounding rain water, building check dams and channels from flowing water. They are called eris (Tamil Nadu), surrangams (Kerala) and kattas (Karnataka).

Question 9.
Find out the source of water in your region!locality. Is water from this source available to all people living in that area ?
Answer:
Water is supplied by municipal corporation through pipes. It is obtained from river/canal (if the same happens to be nearby). In many cases piped water is pumped out from ground by tube wells and stored in raised water tanks.
Municipal water supply is not available to all the residents. Many newly built colonies, slums and unauthorised localities are often without the piped water.

NCERT Chapter End Exercises

Question 1.
What changes would you suggest in your home in order to be environment friendly ?
(CBSE AI 2009, CCE 2012, 2014)
Answer:

  1. Judicious use of electricity by switching off lights and electrical appliances not required,
  2. Replacement of incandescent bulbs with fluorescent, compact fluorescent ones and LED bulbs.
  3. Replacement of electricity or gas operated geysers with solar water heaters,
  4. Replacement of electricity generating sets with solar light,
  5. Having more natural light and ventilation with design supporting warming during winters and cooling during summer,
  6. Reducing wastage of water, food and other articles.
  7. Separation of recyclable waste from non-cyclable waste prior to disposal.
  8. Increasing reuse of containers,
  9. Using cloth bags instead of polythene, plastic or paper bags.

Question 2.
Can you suggest some changes in your school which would make it environment friendly ?
Answer:
Yes.

  1. Rainwater harvesting (RWH) by draining roof top rain for underground seepage,
  2. Plantation of trees and shrubs along the boundary for protection against noise and air pollution. Plants will not only provide more oxygen during the school hours but also have a moderating effect on climate.
  3. Prevention of wastage of electricity and water,
  4. Having compost pits for conversion of plant refuse and other biodegradable wastes into useful resource,
  5. Increasing use of solar energy,
  6. Activating ecoclub.

Question 3.
There are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management offorest produce ? Why do you think so (CBSE Foreign 2010, CCE 2011)
Answer:
The four stakeholders in forests and wildlife are

  1. People living in and around forests who obtain most of their requirements from forests,
  2. Forest department which owns the forests.
  3. Industrialists who obtain raw materials for their industries,
  4. Wildlife and nature enthusiasts. Among them the persons living in and around the forests have traditional knowledge of how best the forests can be managed so that a sustainable yield can be obtained indefinitely. Therefore, authority for management of forest produce should be handed over to them. However, the forest department must monitor the same so that there is no excessive exploitation.

Question 4.
How can you as an individual contribute or make a difference to the management of
(a) Forests and wildlife
(b) Water resources
(c) Coal and petroleum ?
Answer:
(a) Forests and Wildlife:

  1. I will stress on sustainable use of produce from forests and wildlife,
  2. The area under forest cover has to be increased to control global warming.
  3. Form more joint forest management committees,
  4. Separate commercial forestry from natural forestry.

(b) Water Resources. My major stress will be

  1. Recharging of ground water through rain water harvesting, protection to wetlands and digging sponge pits or wells in the beds of rivulets,
  2. Reducing spoilage of water in agriculture by helping formers to switch over to sprinkler system of irrigation, changing conventional method of rice cultivation with system of rice intensification (SRI),
  3. Judicious use of water for domestic and industrial purposes.

(c) Coal and Petroleum:

  1. Higher level of purification to reduce pollution,
  2. Increased use of solar energy,
  3. More investment to commercialise hydrogen powered transport system.

Question 5.
What can you, as an individual, do to reduce your consumption of various natural resources ?
Answer:
Follow the principle of three Rs, i.e, reduce, recycle, reuse.

Question 6.
List five things you have done over the last one week to
(a) Conserve our natural resources
(b) Increase the pressure on our natural resources ?
Answer:
(a) Conservation of Natural Resources

  1. Reduced consumption of electricity by switching off unwanted fans and bulbs,
  2. Reduced consumption of water by closing the tap to prevent overflow of water in the bucket during taking bath,
  3. Used refills instead of purchasing new pens,
  4. I did not waste food,
  5. I have started going to school by school bus instead of using car.

(b) Increase Pressure on Natural Resources

  1. While reading at night on bed, I fell asleep and forgot to switch off the lights,
  2. While brushing my teeth and later taking bath, I did not close the tap, so a lot of water was wasted,
  3. I left the ball pen uncapped, so the ink dried up. I had to throw three ball pens last week,
  4. I am in the habit of using loose sheets for doing rough work. They are then thrown away,
  5. I bring more food in my tiffin than I eat. Daily I throw a lot of food in the dust bin.

Question 7.
On the basis of environmental issues you studied, what changes would you incorporate in your life style in a move towards a sustainable use of our resources ?
Answer:
1. Follow the principle of three Rs — reduce, recycle and reuse.
2. Undertake tree plantation twice a year during days of Van Mahotsava.
3. Where possible, use of public transport, school, bus and car pools.
4. Use of solar energy for as many purposes as possible.

Selection Type Questions

Alternate Response Type Questions
(True/False, Right(√)/Wrong (x), Yes/No)

Question 1.
Presence of coliform bacteria in a water body indicates contamination by industrial effluents.
Question 2.
An environmentally friendly decision is reuse jam and pickle bottles.
Question 3.
Forests are reservoirs of wildlife.
Question 4.
Chipko andolan originated in Haridwar during 1980s.
Question 5.
Check dams are built along seasonal flooded gullies for water harvesting.
Question 6.
Coal and petroleum are non-renewable inexhaustible resource.
Question 7.
An important protective function of forests is reduction of atmospheric pollution.
Question 8.
Forest department has been able to maintain biodiversity by growing pine, Teak and Eucalyptus on large tracts.

Matching Type Questions

Question 9.
Match the columns I and II (single matching) :

Column I

Column II

(a)    Desertification

(b)    Khejri

(c)   Khadin

(d)   Carbon monoxide

(i) Amrita Devi Bishnoi

(ii) Incomplete combustion

(iii)    Deforestation

(iv)   Water harvesting

Question 10.
Match the contents of columns I, II and III (double matching) :

Column I

Column II

Column III

(a)    Flyash

(b)    Kulhs

(c)    Van Mahotsav

(d)    Water pollution

(i) Coliform count

(ii) Coal

(iii)     Water harvesting

(iv)     Afforestation

p.  Himachal Pradesh

q. BOD

r. Toxic chemicals

s. February, July

Question 11.
Mark the resource as I (inexhaustible), R (renewable) and N (non-renewable) (key or check list items):
NCERT Solutions for Class 10 Science Chapter 16 Management of Natural Resources 1

Question 12.
Match stimulus with appropriate response.

Water Harvesting

Karnataka A Tamil Nadu B Kerala C

(i) Surrangams

(ii) Kattas

(iii) Eris

Fill in the Blanks

Question 13. Forests are ………….. hot spots.
Question 14. Amrita Devi Bishnoi sacrificed her life and that of 363 others in for ……………….. protection of …………….. trees.
Question 15. In blood carbon monoxide forms …………… that is unable to transport oxygen.
Question 16. Ganga runs its course of 2500 km from …………….. in Bay of Bengal.
Question 17. To save energy and prevent warming, I use ……………… instead of incandescent bulbs.

Answers:
NCERT Solutions for Class 10 Science Chapter 16 Management of Natural Resources image - 1

NCERT Solutions for Class 10 Science Chapter 16 Management of Natural Resources

Hope given NCERT Solutions for Class 10 Science Chapter 16 are helpful to complete your science homework.

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NCERT Solutions for Class 10 Science Chapter 15 Our Environment

NCERT Solutions for Class 10 Science Chapter 15 Our Environment

These Solutions are part of NCERT Solutions for Class 10 Science. Here we have given NCERT Solutions for Class 10 Science Chapter 15 Our Environment. LearnInsta.com provides you the Free PDF download of NCERT Solutions for Class 10 Science (Biology) Chapter 15 – Our Environment solved by Expert Teachers as per NCERT (CBSE) Book guidelines. All Chapter 15 – Our Environment Exercise Questions with Solutions to help you to revise complete Syllabus and Score More marks.

NCERT Questions

In Text Questions

Question 1.
Why are some substances biodegradable and some non-biodegradable ? (CCE 2011)
Answer:
Biodegradable substances are substances of organic origin which can be broken down by enzymes of saprophytes, e.g., garbage, sewage, livestock waste, agriculture waste. Non-biodegradable substances are man-made substances which cannot be degraded by saprophytes because they lack the enzymes to do so e.g., waste plastic and polythene articles.

More Resources

Question 2..
Give any two ways in which biodegradable substances would affect the environment.
(CBSE Delhi 2007, AI 2009 C)
Answer:

  1. Stink: Within a day or so waste biodegradable substances begin to stink and produce foul gases.
  2. Pests and Pathogens: The decaying biodegradable substances become breeding places of flies and many other pests. They also contain a number of pathogens. Flies and other pests carry the germs to all the places visited by them resulting in spread of diseases.

Question 3.
Give any two ways in which non-biodegradable substances would affect the environment. (CBSE AI 2009 C)
Answer:

  1. Dumping Area: Dumping of non-biodegradable substances on a piece of land converts the same into barren land. It is also called landscape pollution.
  2. Biological Magnification: Pesticides, heavy metals and other chemicals enter water and food chains. They accumulate in toxic proportions and harm all kinds of living organisms. Their concentration also increases with rise in trophic level. Human beings are harmed the most because man lies at the top of every food chain.

Question 4.
What are trophic levels ? Give an example of a food chain and state the trophic levels in it.
Answer:
(a) Trophic Levels. They are steps or divisions of food chain which are characterised by particular methods of obtaining food, e.g., producers (T1), herbivores (T2), primary carnivores (T3), etc.
NCERT Solutions for Class 10 Science Chapter 15 Our Environment image - 1
(b) Flow of Energy Through Food Chain. Energy enters a food chain through producers. Producers or green plants trap solar energy and convert it into chemical energy of food during photosynthesis. From producers energy passes into herbivores. A lot of energy dissipates during transfer and utilization of food energy by herbivores (10% law). From herbivores the food energy passes into primary carnivores, again with a lot of dissipation. Only about 10% of herbivore energy is passed into body mass of primary carnivores. From primary carnivores, nearly 10% energy passes into secondary carnivores and so on. It is ultimately lost as heat.

Question 5.
What is the role of decomposers in the ecosystem ?
Answer:
Ecosystem is a self-contained ecological system which consists of a distinct biotic community and the physical environment, both interacting and exchanging materials between them. It is a structural and functional unit of biosphere. Ecosystem is an open system which requires a regular input of energy and circulation of matter for its sustenance. Different ecosystems are in contact with one another. Though they are distinct, but exchange of materials can occur amongst them. Ecosystem can be small (e.g., rotting piece of wood) or large (e.g., forest, ocean), temporary (e.g., rain fed pond) or permanent (e.g., lake, forest), natural or artificial.
Natural Ecosystems: They are ecosystems which develop in nature without human support. Natural ecosystems are of two types, terrestrial and aquatic. Terrestrial ecosystems occur over land. They are of three major types -— desert, grassland and forest. Aquatic ecosystems are found in water bodies, e.g., ponds, lakes, rivers (fresh water), estuaries, marine (salt water).
Artificial Ecosystems: They are ecosystems which have been p/g. 5.7. An aquarium. created and are maintained by human beings. Artificial ecosystems are also called man-made or anthropogenic ecosystems. Agroecosystem is the largest man-made ecosystem. Garden is a common artificial ecosystem maintained by most institutes. It has various types of plants grown and maintained by gardener — grass, trees, flower bearing plants like Rose, Jasmine, Sunflower. A number of animals become residents and visitors of the garden. Aquarium is another artificial ecosystem.

Question 6.
What is ozone and how does it affect any ecosystem ?
Answer:
Definition of Ozone: Ozone is a triatomic molecule made up of three atoms of oxygen, O3.
Effect:

  1. Protection against ultraVoilet rays if present in stratosphere,
  2. Ozone dissipates the energy of ultraviolet rays by undergoing dissociation following by reassociation
    NCERT Solutions for Class 10 Science Chapter 15 Our Environment image - 2

If present in the atmosphere of ecosystem, it is highly toxic causing injury to mucous membranes, eye irritation and internal haemorrhages in animals and humans. It harms plants by destroying photosynthetic cells producing necrosis.

Question 7.
How can you help in reducing the problem of waste disposal ? Give any tivo methods.
Answer:
Waste disposal is becoming the biggest problem of all local bodies. It is consuming a big chunk of their revenues. Even then the points of collection are turning into stinking areas. Transport of waste to disposal site is seldom perfect. There is stink all the way. A lot of waste is thrown on the roads by the vehicles carrying the waste.
The quantity of waste can be reduced if you form the habit of separation of waste into biodegradable and non-biodegradable parts.

  1. Non-biodegradable Waste. Most often the non-biodegradable waste is recycled. It is taken away by rag pickers.
  2. Biodegradable Waste. Biodegradable waste is putressible. It can be composted or vermicomposted to prepare compost for your kitchen gardens. The technique can also be used in schools and other institutions. Some institutes in big cities have installed incinerators for disposal of combustible components of waste. Hospital waste is being compulsorily incinerated to reduce contamination and spread of diseases.

NCERT Chapter End Exercises

Question 1.
Which of the following groups contains only easily biodegradable items ?
(A) Grass, flower and leather
(B) Grass, wood and plastic
(C) Fruit peels, cake and lime juice ,
(D) Cake, wood and grass.
Answer:
(A), (C), (D).

Question 2.
Which of the following constitute a food chain
(A) Grass, wheat and mango
(B) Grass, goat and human
(C) Goat, cow and elephant
(D) Grass, fish and goat.
Answer:
(B).

Question 3.
Which of the following are environment friendly practices ?
(A) Carrying cloth bags to put purchases in while shopping
(B) Switching off unnecessary lights and fans
(C) Walking to school instead of getting your mother to drop you on her scooter
(D) All the above.
Answer:
(D).

Question 4.
What will happen if you kill all the orgainsms in one trophic level ?
Answer:
Higher Trophic Level. All the organisms will be starved and die. Lower Trophic Level. The organisms will increase in number much beyond the carrying capacity of the enviroment. They will become weak and fall easy prey to various diseases, ultimately resulting in decline in population. The ecosystem may get converted into a desert.

Question 5.

  1. Will the impact of removing all the organisms in a trophic level be different for different trophic levels ?
  2. Can the organisms of any trophic level be removed without causing any damage to the ecosystem ?

Answer:

  1. Yes. Impact of removing all the organisms of a trophic level depends upon the trophic level. Removal of producers will kill all the consumers. Killing of carnivores will increase the number of herbivores which in turn will eat up all the producers. They would themselves die of starvation. However, if herbivores are removed, all the carnivores of the area will die. The plants which are dependent upon animals for pollination will fail to reproduce and die ultimately. Others would persist and increase in number, again much beyond the carrying capacity of the environment.
  2. No. Removal of all the organisms of a trophic level will disturb the ecosystem – killing of higher trophic level organisms and explosion in populations of lower level organisms. Higher number of lower trophic level organisms will adversely affect the ecosystem by consuming whole or major part of their prey.

Question 6.
What is biological magnification ? Will the levels of this magnification be different at different levels of the ecosystem ?
Answer:
Definition: Biological magnification is increase in the concentration of a chemical per unit weight of the organisms with the successive rise in trophic level. In one study it was found that concentration of harmful chemical like DDT will increase 80,000 times the concentration present in water.
Levels of Magnification at Different Levels of Ecosystem. Levels of biomagnification of a chemical will be different at different levels of ecosystem. In one study it was found that concentration of a pesticide was 0.002 ppm in water, 0.05 ppm in plankton, 2.4 ppm in fish and 16.0 ppm in fish eating bird.
NCERT Solutions for Class 10 Science Chapter 15 Our Environment image - 3

Question 7.
What are the problems caused by the nonbiodegradable waste we generate ?
Answer:

  1. Volume: Being non-biodegradable, the volume of these wastes will not decrease by natural process of decomposition.
  2. Land Use: They have to be dumped over land. The land becomes unfit for any other purpose.
  3. Heavy Metals: Heavy metals present in industrial wastes (e.g., copper, lead, chromium, nickel, mercury) remain in the soil indefinitely. Slowly they pass into vegetation and crops harming both humans and animals.
  4. Pesticides and Other Toxins: They pollute underground water, surface water and soil. The chemicals enter food chain and become concentrated, harming animals and humans.
  5. Rag Pickers: In the process of removing recyclable materials from solid wastes, the rag pickers are exposed to many diseases and toxins.
  6. Recycling: Recycling of materials produces only’inferior quality products. Recycling of polythene and plastic is accompanied by release of carcinogenic toxins like dioxins and furans.

Question 8.
If all the waste we generate is biodegradable, will this have no impact on the environment ?
Answer:
The impact on the environment will depend upon the system of collecting, transporting and disposal of biodegradable waste. If it is regular and clean, the impact will be little in urban areas. Only some effect will be observed at disposable site which will emit foul gases and expose the sanitary workers to contamination. The same can also be reduced by increased use of machines and wearing of protective gear by the sanitary workers.

Question 9.
Why is damage to the ozone layer a cause of concern What steps are being taken to limit this damage ?
Answer:
Cause of Concern: Ozone layer present in the stratosphere has thinned out by about 8% over the equator and more so over the antarctica where a big ozone hole appears every year.
This has increased the level of UV-B radiations reaching the earth by 15-20%. These radiations are causing increased number of skin cancers, cataracts and reduced immunity in human beings. There is increased incidence of blinding of animals, death of young ones, reduced photosynthesis, higher number of mutations and damage to articles.
Steps to Limit Damage:

  1. Ban on production and use of halons.
  2. Ban on production and use of chlorofluorocarbons.

Selection Type Questions

Alternate Response Type Questions
(True/False, Right(√)/Wrong (x), Yes/No)

Question 1.
Wastes are of two types, biodegradable and non-biodegradable.
Question 2.
Non-biodegradable articles are the ones which cannot be digested.
Question 3.
Ozone is formed in stratosphere by action of ultravoilet radiations on oxygen.
Question 4.
Earth is kept warm due to green house flux.
Question 5.
Rag pickers remove reusable articles.
Question 6.
Pyrolysis is aerobic combustion while incineration is anaerobic combustion.
Question 7.
Biodegradable wastes should be separated and kept in blue colour bins for garbage collectors.
Question 8.
Food web ensures survival of all types of trophic levels.

Matching Type Questions

Question 9.
Match the articles in columns I and II (single matching) :

Column I

Column II

(a) Hawk (i) Producer
(b) Hare (ii) Top carnivore
(c) Grass (iii) Green house gas
(d) Carbon dioxide (iv) Herbivore

Question 10.
Match the contents of columns I, II and III (double matching)

Column I

Column II

Column III

(a)    Ecosystem

(b)    Producers

(c)    Omnivores

(d)    Persistent pesticide

(i) Food chain

(ii) Abiotic components

(iii) Transducer

(iv) Plant food

p.  Food energy

q.  Biomagnification

r. Animal food

s. Biotic components

Question 11.
To what trophic level (T1, T2, T3, T4) do the following belong (key or check list items)
NCERT Solutions for Class 10 Science Chapter 15 Our Environment image - 4

Question 12.
Match each stimulus with appropriate response :

Activity

Deforestation (A) Increase runoflf (B)

Destruction of wild life (C)

(i) Hunting

(ii) Felling of trees

(iii) Litter Collection

Fill In the Blanks

Question 13. Waste substances that are broken down by microbes are called ………. : ………… .
Question 14. Gardens and crop fields are ………………. ecosystems.
Question 15. Microorganisms are called ……………… as they break down the complex organic remains into simple inorganic substances.
Question 16. Decrease in ozone in stratosphere is linked to release of synthetic chemicals like ……………… .
Question 17. Improvement in life style often results in increased generation of …………. : ………… material.

Answers:
NCERT Solutions for Class 10 Science Chapter 15 Our Environment image - 5

NCERT Solutions for Class 10 Science Chapter 15 Our Environment

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