Online Education for RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS

Online Education for RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS

These Solutions are part of Online Education RD Sharma Class 9 Solutions. Here we have given RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS

Other Exercises

Mark the correct alternative in each of the following:
Question 1.
If the length of a chord of a circle is 16 cm and is at a distance of 15 cm from the centre of the circle, then the radius of the circle is
(a) 15 cm
(b) 16 cm
(c) 17 cm
(d) 34 cm
Solution:
Length of chord AB of circle = 16 cm
Distance from the centre OL = 15 cm
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q1.1
Let OA be the radius, then in right ∆OAL,
OA2 = OL2 + AL2
16
= (15)2 + \(\frac { 16 }{ 2 }\) = 152 + 82
= 225 + 64 = 289 = (17)2
∴ OA = 17 cm
Hence radius of the circle = 17 cm (c)

Question 2.
The radius of a circle Js 6 cm. The perpendicular distance from the centre of the circle to the chord which is 8 cm in length, is

RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQ Q2.3
Solution:
Radius of the cirlce (r) = 6 cm
Perpendicular distance from centre = ?
Length of chord = 8 cm
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q2.1
Let AB be chord, OL is the distance
In right ∆OAL
OA2 = AL2 + OL2
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q2.2

Question 3.
If O is the centre of a circle of radius r and AB is a chord of the circle at a distance \(\frac { r }{ 2 }\) from O, then ∠BAO =
(a) 60°
(b) 45°
(c) 30°
(d) 15°
Solution:
r is the radius of the circle with centre O
AB is the chord, at a distance of \(\frac { r }{ 2 }\) from the centre
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q3.1

Question 4.
ABCD is a cyclic quadrilateral such that ∠ADB = 30° and ∠DCA = 80°, then ∠DAB=
(a) 70°
(b) 100°
(c) 125°
(d) 150°
Solution:
ABCD is a cyclic quadrilateral ∠DCA = 80° and ∠ADB = 30°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q4.1
∵∠ADB = ∠ACB (Angles in the same segment)
∴ ∠ACB = 30°
∴ ∠BCD = 80° + 30° = 110°
∵ ABCD is a cyclic quadrilateral
∴∠BAD + ∠BCD = 180°
⇒ ∠BAD + 110°= 180°
⇒ ∠BAD = 180°- 110° = 70°
or ∠DAB = 70° (a)

Question 5.
A chord of length 14 cm is at a distance of 6 cm from the centre of a circle. The length of another chord at a distance of 2 cm from the centre of the circle is
(a) 12 cm
(b) 14 cm
(c) 16 cm
(d) 18 cm
Solution:
In a circle AB chord = 14 cm
and distance from centre OL = 6 cm
Let r be the radius of the circle, then OA2 = AL2 + OL2
⇒ r2 = (7)2 + (6)2 = 49 + 36 = 85
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q5.1
In the same circle length of another chord CD = ?
Distance from centre = 2 cm
∴ r2 = OM2 + MD2
⇒ 85 = (2)2 + DM2
⇒ 85 = 4 + DM2
⇒ DM2 = 85-4 = 81 = (9)2
∴ DM = 9
∴ CD = 2 x DM = 2 x 9 = 18 cm
∴Length of another chord = 18 cm (d)

Question 6.
One chord of a circle is known to be 10 cm. The radius of this circle must be
(a) 5 cm
(b) greater than 5 cm
(c) greater than or equal to 5 cm
(d) less than 5 cm
Solution:
Length of chord of a circle = 10 cm
Length of radius of the circle greater than half of the chord
More than \(\frac { 10 }{ 2 }\) = 5 cm (b)

Question 7.
ABC is a triangle with B as right angle, AC = 5 cm and AB = 4 cm. A circle is drawn with O as centre and OC as radius. The length of the chord of this circle passing through C and B is
(a) 3 cm
(b) 4 cm
(c) 5 cm
(d) 6 cm
Solution:
In right ∆ABC, ∠B = 90°
AC = 5 cm, AB = 4 cm
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q7.1
∴ BC2 = AC-AB2
= 52 – 42 = 25 – 16
= 9 = (3)2
∴ BC = 3 cm
∴ Length of chord BC = 3 cm (a)

Question 8.
If AB, BC and CD are equal chords of a circle with O as centre, and AD diameter then ∠AOB =
(a) 60°
(b) 90°
(c) 120°
(d) none of these
Solution:
In a circle chords AB = BC = CD
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q8.1
O is the centre of the circle
∴ ∠AOB = cannot be found (d)

Question 9.
Let C be the mid-point of an arc AB of a circle such that m \(\breve { AB }\) = 183°. If the region bounded by the arc ACB and line segment AB is denoted by S, then the centre O of the circle lies
(a) in the interior of S
(b) in the exterior of S
(c) on the segment AB
(d) on AB and bisects AB
Solution:
\(\breve { AB }\) = 183°
∴ AB is the diameter of the circle with centre O and C is the mid point of arc AB
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q9.1
Line segment AB = S
∴ Centre will lie on AB (c)

Question 10.
In a circle, the major arc is 3 ti.nes the minor arc. The corresponding central angles and the degree measures of two arcs are
(a) 90° and 270°
(b) 90° and 90°
(c) 270° adn 90°
(d) 60° and 210°
Solution:
In a circle, major arc is 3 times the minor arc i.e. arc ACB = 3 arc ADB
∴ Reflex ∠AOB = 3∠AOB
But angle at O = 360°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q10.1
and let ∠AOB = x
Then reflex ∠ADB = x
x + 3x – 360°
⇒ 4x = 360°
⇒ x = \(\frac { { 62 }^{ \circ } }{ 2 }\)  = 90°
∴ 3x = 90° x 3 = 270°
Here angles are 270° and 90° (c)

Question 11.
If A and B are two points on a circle such that m(\(\breve { AB }\)) = 260°. A possible value for the angle subtended by arc BA at a point on the circle is
(a) 100°
(b) 75°
(c) 50°
(d) 25°
Solution:
A and B are two points on the circle such that reflex ∠AOB = 260°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q11.1
∴ ∠AOB = 360° – 260° = 100°
C is a point on the circle
∴ By joining AC and BC,
∠ACB = \(\frac { 1 }{ 2 }\)∠AOB = \(\frac { 1 }{ 2 }\) x 100° = 50° (c)

Question 12.
An equilateral triangle ABC is inscribed in a circle with centre O. The measures of ∠BOC is
(a) 30°
(b) 60°
(c) 90°
(d) 120°
Solution:
∆ABC is an equilateral triangle inscribed in a circle with centre O
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q12.1
∴ Measure of ∠BOC = 2∠BAC
= 2 x 60° = 120° (d)

Question 13.
If two diameters of a circle intersect each other at right angles, then quadrilateral formed by joining their end points is a
(a) rhombus
(b) rectangle
(c) parallelogram
(d) square
Solution:
Two diameter of a circle AB and CD intersect each other at right angles
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q13.1
AD, DB, BC and CA are joined forming a quad. ABCD.
∵ The diagonals are equal and bisect each other at right angles
∴ ACBD is a square (d)

Question 14.
In ABC is an arc of a circle and ∠ABC = 135°, then the ratio of arc \(\breve { AB }\) to the circumference is
(a) 1 : 4
(b) 3 : 4
(c) 3 : 8
(d) 1 : 2
Solution:
Arc ABC of a circle and ∠ABC = 135°
Join OA and OC
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q14.1
∴ Angle subtended by arc ABC at the centre = 2 x ∠ABC = 2 x 135° = 270°
Angle at the centre of the circle = 360°
∴ Ratio with circumference = 270° : 360° = 3:4 (b)

Question 15.
The chord of a circle is equal to its radius. The angle subtended by this chord at the minor arc of the circle is
(a) 60°
(b) 75°
(c) 120°
(d) 150°
Solution:
The chord of a circle = radius of the circle In the figure OA = OB = AB
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q15.1
∴ ∠AOB = 60°
(Each angle of an equilateral = 60°) (a)

Question 16.
PQRS is a cyclic quadrilateral such that PR is a diameter of the circle. If ∠QPR = 67° and ∠SPR = 72°, then ∠QRS =
(a) 41°
(b) 23°
(c) 67°
(d) 18°
Solution:
PQRS is a cyclic quadrilateral with centre O and ∠QPR = 67°
∠SPR = 72°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q16.1
∴ ∠QPS = 67° + 72° = 139°
∵ ∠QPS + ∠QRS = 180° (Sum of opposite angles of a cyclic quad.)
⇒ 139° + ∠QRS = 180°
⇒ ∠QRS = 180° – 139° = 41° (a)

Question 17.
If A, B, C are three points on a circle with centre O such that ∠AOB = 90° and ∠BOC = 120°, then ∠ABC =
(a) 60°
(b) 75°
(c) 90°
(d) 135°
Solution:
A, B and C are three points on a circle with centre O
∠AOB = 90° and ∠BOC = 120°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q17.1
∴ ∠AOC = 360° – (120° + 90°)
= 360° -210°= 150°
But ∠AOC is at the centre made by arc AC and ∠ABC at the remaining part of the circle
∴ ∠ABC = \(\frac { 1 }{ 2 }\) ∠AOC
= \(\frac { 1 }{ 2 }\) x 150° = 75° (b)

Question 18.
The greatest chord of a circle is called its
(a) radius
(b) secant
(c) diameter
(d) none of these
Solution:
The greatest chord of a circle is called its diameter. (c)

Question 19.
Angle formed in minor segment of a circle is
(a) acute
(b) obtuse
(c) right angle
(d) none of these
Solution:
The angle formed in minor segment of a circle is obtuse angle. (b)

Question 20.
Number of circles that can be drawn through three non-collinear points is
(a) 1
(b) 0
(c) 2
(d) 3
Solution:
The number of circles that can pass through three non-collinear points is only one. (a)

Question 21.
In the figure, if chords AB and CD of the circle intersect each other at right angles, then x + y =
(a) 45°
(b) 60°
(c) 75°
(d) 90°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q21.1
Solution:
In the circle, AB and CD are two chords which intersect each other at P at right angle i.e. ∠CPB = 90°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q21.2
∠CAB and ∠CDB are in the same segment
∴ ∠CDB = ∠CAB = x
Now in ∆PDB,
Ext. ∠CPB = ∠D + ∠DBP
⇒ 90° = x + y (∵ CD ⊥ AB)
Hence x + y = 90° (d)

Question 22.
In the figure, if ∠ABC = 45°, then ∠AOC=
(a) 45°
(b) 60°
(c) 75°
(d) 90°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q22.1
Solution:
∵ arc AC subtends
∠AOC at the centre of the circle and ∠ABC
at the remaining part of the circle
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q22.2
∴ ∠AOC = 2∠ABC
= 2 x 45° = 90°
Hence ∠AOC = 90° (d)

Question 23.
In the figure, chords AD and BC intersect each other at right angles at a point P. If ∠D AB = 35°, then ∠ADC =
(a) 35°
(b) 45°
(c) 55°
(d) 65°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q23.1
Solution:
Two chords AD and BC intersect each other at right angles at P, ∠DAB = 35°
AB and CD are joined
In ∆ABP,
Ext. ∠APC = ∠B + ∠A
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q23.2
⇒ 90° = ∠B + 35°
∠B = 90° – 35° = 55°
∵ ∠ABC and ∠ADC are in the same segment
∴ ∠ADC = ∠ABC = 55° (c)

Question 24.
In the figure, O is the centre of the circle and ∠BDC = 42°. The measure of ∠ACB is
(a) 42°
(b) 48°
(c) 58°
(d) 52°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q24.1
Solution:
In the figure, O is the centre of the circle
∠BDC = 42°
∠ABC = 90° (Angle in a semicircle)
and ∠BAC and ∠BDC are in the same segment of the circle.
∴ ∠BAC = ∠BDC = 42°
Now in ∆ABC,
∠A + ∠ABC + ∠ACB = 180° (Sum of angles of a triangle)
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q24.2
⇒ 42° + 90° + ∠ACB = 180°
⇒ 132° + ∠ACB – 180°
⇒ ∠ACB = 180° – 132° = 48° (b)

Question 25.
In a circle with centre O, AB and CD are two diameters perpendicular to each other. The length of chord AC is
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q25.1
Solution:
AB and CD are two diameters of a circle with centre O
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q25.2

Question 26.
Two equal circles of radius r intersect such that each passes through the centre of the other. The length of the common chord of the circles is
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q26.1
Solution:
Two equal circles pass through the centre of the other and intersect each other at A and B
Let r be the radius of each circle
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q26.2
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q26.3

Question 27.
If AB is a chord of a circle, P and Q are the two points on the circle different from A and B,then
(a) ∠APB = ∠AQB
(b) ∠APB + ∠AQB = 180° or ∠APB = ∠AQB
(c) ∠APB + ∠AQB = 90°
(d) ∠APB + ∠AQB = 180°
Solution:
AB is chord of a circle,
P and Q are two points other than from points A and B
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q27.1
∵ ∠APB and ∠AQB are in the same segment of the circle
∴ ∠APB = ∠AQB (a)

Question 28.
AB and CD are two parallel chords of a circle with centre O such that AB = 6 cm and CD = 12 cm. The chords are on the same side of the centre and the distance between them is 3 cm. The radius of the circle is
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q28.1
Solution:
AB and CD are two parallel chords of a circle with centre O
Let r be the radius of the circle AB = 6 cm, CD = 12 cm
and distance between them = 3 cm
Join OC and OA, LM = 3 cm
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q28.2
Let OM = x, then OL = x + 3
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q28.3
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q28.4

Question 29.
In a circle of radius 17 cm, two parallel chords are drawn on opposite side of a diameter. This distance between the chords is 23 cm. If the length of one chord is 16 cm then the length of the other is
(a) 34 cm
(b) 15 cm
(c) 23 cm
(d) 30 cm
Solution:
Radius of a circle = 17 cm
The distance between two parallel chords = 23 cm
AB || CD and LM = 23 cm
Join OA and OC,
∴ OA = OC = 17 cm
Let OL = x, then OM = (23 – x) cm
AB = 16 cm
Now in right ∆OAL,
OA2 = OL22 + AL2
⇒ (17)2 = x2 + AL2
⇒ 289 = x2 + AL2
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q29.1
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q29.2

Question 30.
In the figure, O is the centre of the circle such that ∠AOC = 130°, then ∠ABC =
(a) 130°
(b) 115°
(c) 65°
(d) 165°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q30.1
Solution:
O is the centre of the circle and ∠AOC = 130°
Reflex ∠AOC = 360° – 130° = 230°
RD Sharma Class 9 Solutions Chapter 15 Areas of Parallelograms and Triangles MCQS Q30.2
Now arc ADB subtends ∠AOC at the centre and ∠ABC at the remaining part of the circle
∴ ∠ABC = \(\frac { 1 }{ 2 }\)reflex ∠AOC
= \(\frac { 1 }{ 2 }\) x 230°= 115° (b)

 

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Online Education NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules

Online Education NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules

These Solutions are part of Online Education NCERT Solutions for Class 9 Science. Here we have given NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules. LearnInsta.com provides you the Free PDF download of NCERT Solutions for Class 9 Science (Chemistry) Chapter 3 – Atoms and Molecules solved by Expert Teachers as per NCERT (CBSE) Book guidelines. All Chapter 3 – Atoms and Molecules Exercise Questions with Solutions to help you to revise complete Syllabus and Score More marks.

More Resources

NCERT IN TEXT PROBLEMS

IN TEXT QUESTIONS

Question 1.
In a reaction, 5.3 g of sodium carbonate reacted with 6.0 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g of water and 8.2 g of sodium ethanoate. Show that these observations are in agreement with the law of conservation of mass. (CBSE 2012)
Answer:
The chemical reaction leading to products is :
sodium carbonate + ethanoic acid ———–> sodium ethanoate + carbon dioxide + water.
Mass of reactants = (5.3 + 6.0) = 1.3 g
Mass of products = (8.2 + 2.2 + 0.9) = 11.3 g.
The reactants and products have same mass. This means that there was no loss of mass during the reaction. Therefore, the data is in agreement with law of conservation of mass.

Question 2.
Hydrogen and oxygen combine in the ratio of 1 : 8 by mass to form water. What mass of oxygen gas would be required to react with 3 g of hydrogen gas ?
Answer:
According to available data,
Mass of oxygen combining with 1 g of hydrogen = 8 g.
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 1
Question 3:
Which postulate of Dalton’s Atomic theory is the basis of law of conservation of mass ? (CBSE 2012)
Answer:
The law of conservation mass is based on the following postulate of Dalton’s Atomic theory.
“Atoms can neither be created nor destroyed during a physical change or a chemical reaction.”

Question 4.
Which postulate of Dalton’s Atomic theory can explain the law of definite proportions ?
Answer:
The law of definite proportions is based on the following postulate of Dalton’s Atomic theory.
“All atoms of a particular element are identical in every respect. This means that they have same mass, same size and also same chemical properties.”

Question 5.
Define atomic mass unit.
Answer:
Atomic mass unit may be defined as :
The mass of one-twelfth (1/12) of the mass of one atom of carbon taken as 12 u. It is represented as 1 u (unified mass).

Question 6.
Why is not possible to see an atom with naked eye ?
Answer:
It is not possible to see an atom with naked eye because of its extremely small size. For example, the radius of an atom of hydrogen is of the order of 10-10 m. Actually an atom is regarded as a microscopic particle. These microscopic particles cannot be seen with naked eye.

Question 7.
Write down the formulae of :
(i) sodium oxide
(ii) aluminium chloride
(iii) sodium sulphide
(iv) magnesium hydroxide.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 2
Question 8.
Write the names of the compounds represented by the following formulae :
(i) Al2(SO4)3
(ii) CaCl2
(Hi) K2SO4
(iv) KNO3
(v) CaCO3.
Answer:
(i) Aluminium sulphate
(ii) Calcium chloride
(iii) Potassium sulphate
(iv) Potassium nitrate
(v) Calcium carbonate

Question 9.
What is meant by the term chemical formula ?
Answer:
Molecule represents a group of two or more atoms (same or different) chemically bonded to each other and held tightly by strong attractive forces. Molecules are represented in terms of symbols of constituting atoms and it is known as chemical formula.

Question 10.
How many atoms are present in
(i) H2S molecule
(ii) PO43- ion ?
Answer:
(i) Three
(ii) Five.

Question 11.
Calculate the molecular masses of :
(i) H2
(ii) O2
(iii) Cl2
(iv) CO2
(v) CH4
(vi) C2H6
(vii) C2H4
(viii) NH3
(ix) CH3OH.
Answer:
(i) Hydrogen (H2)
Molecular mass of H2 = 2 x Atomic mass of H = (2 x 1 u) = 2 u.
(ii) Oxygen (O2)
Molecular mass of O2 = 2 x Atomic mass of O = (2 x 16 u) = 32 u.
(iii) Chlorine (CI2)
Molecular mass of Cl2 = 2 x Atomic mass of Cl = (2 x 35’5 u) = 71 u.
(iv) Carbon dioxide (CO2)
Molecular mass of CO2 = (1 x Atomic mass of C) + (2 x Atomic mass of O)
= (1 x 12 u) + (2 x 16 u) = 12 u + 32 u = 44 u.
(v) Methane (CH4)
Molecular mass of CH4 = ( 1 x Atomic mass of C) + (4 x Atomic mass of H)
= ( 1 x 12 u) + (4 x 1 u) = 16 u.
(vi) Ethane (C2H6)
Molecular mass of C2H6 = (2 x Atomic mass of C) + (6 x Atomic mass of H)
= (2 x 12 u) + (6 x 1 u) = 30 u.
(vii) Ethylene (C2H4)
Molecular mass of C2H4 =(2 x Atomic mass of C) + (4 x Atomic mass of H)
= (2 x 12 u) + (4 x 1 u) = 28 u.
(viii) Ammonia (NH3)
Molecular mass of NH3 = (1 x Atomic mass ofN) + (3 x Atomic mass of H)
= (1 x 14 u) + ( 3 x 1 u) = 17 u.
(ix) Methyl alcohol (CH3OH)
Molecular mass of CH3OH = (1 x Atomic mass of C) + (4 x Atomic mass of H)
+ (1 x Atomic mass of O)
= (1 x 12 u) + (4 x 1 u) + (1 x 16 u) = 32 u.

Question 12.
Calculate the formula unit mass of :
(i) ZnO
(ii) Na2O
(iii) K2CO3.
Given : Atomic masses of Zn = 65 u, Na = 23 u, K = 39 u, C = 12 u and O = 16 u.
Answer:
(i) Formula unit mass of ZnO (Zinc oxide)
= (1 x Atomic mass of Zn) +(1 x Atomic mass of O)
= (1 x 65 u) + (1 x 16 u) = 81 u.
(ii) Formula unit mass of Na2O (Sodium oxide)
= (2 x Atomic mass of Na) + (1 x Atomic mass of O)
= (2 x 23 u) + (1 x 16 u) = 62 u.
(iii) Formula unit mass of K2CO3 (Potassium carbonate).
= (2 x Atomic mass of K) + (1 x Atomic mass of C) + (3 x Atomic mass of O)
= (2 x 39 u) + (1 x 12 u) + (3 x 16 u) = 138 u

Question 13.
Calculate the number of moles of the following :
(i) 52 g of He
(ii) 12.044 x 1023 atoms of He.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 3
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 4

Question 14.
Calculate the number of particles in each of the following :
(i) 46 g of sodium atoms
(ii) 8 g of oxygen (O2)
(iii) 0.1 mole of carbon atoms.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 5

Question 15.
If one mole of carbon weighs 12 grams, what is the mass (in gram) of one atom of carbon ?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 6

Question 16.
Which has more number of atoms ?
(a) 100 grams of sodium
(b) 100 grams of iron
(Given : atomic mass of Na = 23 u ; Fe = 56 u)
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 7

NCERT END EXERCISE

Question 1.
0.24 g of sample of a compound of oxygen and boron was found by analysis to contain 0.096 g of boron
and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 8

Question 2.
When 3.0 g of carbon is burnt in 8.0 g of oxygen, 11.0 g of carbon dioxide is formed. What mass of carbon dioxide will be formed when 3.0 g of carbon is burnt in 50.0 g of oxygen ? Which law of chemical combination will govern your answer ? (CBSE 2011, 2012)
Answer:
Carbon and oxygen react to form carbon dioxide according to the equation Carbon (C) + Oxygen (O2) > Carbon dioxide (CO2)
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 9
In the first case :
3.0 g of carbon are burnt in 8.0 g of oxygen to form 11.0 g of CO2 In the second case :
3.0 g of carbon must also combine with 8.0 g of oxygen only. This means that (50 – 8) = 42 g of oxygen will remain unreacted.
The mass of CO2 in this case must be also 11 g.
The answer is based on Law of constant proportions.
In the second case, only 8.0 g of oxygen react although 50.0 g are available. This shows that the mass of carbon dioxide (11.0 g) formed depends upon the mass of carbon (3.0 g) or the substance present in smaller amount. In general, the substance (element or compound) present in smaller amount in a reaction limits the participation of the other reactants. It is quite often called limiting reactant. Carbon is the limiting reactant in this case. It limits the participation of oxygen and also the formation of carbon dioxide.

Question 3.
What are polyatomic ions ? Give examples. (CBSE 2015)
Answer:
Polyatomic ions are the group of atoms which carry either positive charge (cations) or negative charge (anions). For example,

  1. Carbonate ion (CO3)2-
  2. Nitrate ion (NO3)
  3. Ammonium ion (NH4)+
  4. Phosphate ion (PO4)3-.

Question 4.
Write the chemical formulae of the following :
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 10

Question 5.
Give the names of the elements present in the following compounds :
(a) Quick lime
(b) Hydrogen bromide
(c) Baking powder
(d) Potassium sulphate.
Answer:
The names of elements present can be given only if the chemical formula of the compound is known. For example,
(a) Quick lime : It is the commercial name of the compound. Its chemical name is calcium oxide and the
chemical formula is CaO.
Elements present : calcium (Ca) : oxygen (O).
(b) Hydrogen bromide : The chemical formula of the compound is HBr
Elements present : hydrogen (H) ; bromine (Br).
(c) Baking powder : It is the commercial name of the compound. Its chemical name is sodium hydrogen carbonate and the chemical formula is NaHCO3
Elements present : sodium (Na), hydrogen (H), carbon (C), oxygen (O).
(d) Potassium sulphate : The chemical formula of the compound is K2SO4
Elements present : potassium (K), sulphur (S), oxygen (O).

Question 6.
Calculate the molar mass of the following substances :
(a) Ethyne, C2H2
(b) Sulphur molecule, S8
(c) Phosphorus molecule, P4 (Atomic mass of phosphorus = 31)
(d) Nitric acid, HNO3
(e) Hydrochloric acid, HCl.
Answer:
(a) Ethyne, C2H2
Molar mass of C2H2 = (2 x Atomic mass of C) + (2 x Atomic mass of H)
= (2 x 12 u) + (2 x 1 u) = 26 u.
(b) Sulphur molecule, S8
Molar mass of S8 = 8 x Atomic mass of S = (8 x 32 u) = 256 u
(c) Phosphorus molecule, P4
Molar mass of P4 =4 x Atomic mass of P = (4 x 31 u) = 124 u
(d) Nitric acid, HNO3
Molar mass of HNO3 = (1 x Atomic mass of H) + (1 x Atomic mass of N) + ( 3 x Atomic mass of O)
= (1 x 1 u) + (1 x 14 u) + (3 x 16 u) = 63 u.
(e) Hydrochloric acid, HCl.
Molar mass of HCl = (1 x Atomic mass of H) + (1 x Atomic mass of Cl)
= (1 x 1 u) + (1 x 35.5 u) = 36.5 u.

Question 7.
What is the mass of :
(a) 1 mole of nitrogen atoms ?
(b) 4 moles of aluminium atoms (Atomic mass of aluminium = 27) ?
(c) 10 moles of sodium sulphite (Na2SO3) ?
Answer:
(a) 1 mole of nitrogen atoms
Mass of 1 mole of nitrogen (N) atoms = 14 u
(b) 4 moles of aluminium atoms
Mass of 1 mole of aluminium (Al) atoms = 27 u
Mass of 4 moles of aluminium (Al) atoms = 4 x 27 = 108 u
(c) 10 moles of sodium sulphite (Na2SO3)
Molar mass of Na2SO3 = 2 x Atomic mass of Na + Atomic mass of S + 3 x Atomic mass of O
= 2 x 23 + 32 + 3 x 16 = 126 u
1 mole of sodium sulphite has mass = 126 u
10 moles of sodium sulphite have mass = 10 x 126 = 1260 u.

Question 8.
Convert into moles
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 11

Question 9.
What is the mass of :
(a) 0.2 mole of oxygen atoms ?
(b) 0.5 mole of water molecules ?
Answer:
(a) 0.2 mole of oxygen atoms
Mass of 1 mole of oxygen (O) atoms = 16 u
Mass of 0.2 mole of oxygen (O) atoms = 0.2 x 16 = 3.2 u
(b) 0.5 mole of water molecules
Mass of 1 mole of water (H2O) molecules = 2 x 1 + 16 = 18 u
Mass of 0.5 mole of water (H2O) molecules = 0.5 x 18 = 9 u.

Question 10.
Calculate the number of molecules of sulphur (Sg) present in 16 g of solid sulphur.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 12

Question 11.
Calculate the number of aluminium ions in 0.051 g of aluminium oxide (Al2O3). (CBSE 2012)
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 13

VERY SHORT ANSWER QUESTIONS

Question 1.
Out of atoms and molecules, which can exist independently ?
Answer:
Molecules can exist independently. However, the atoms of noble gases (He, Ne, Ar, Kr, Xe) can also exist independently.

Question 2.
What does the symbol ‘u’ represent ?
Answer:
The symbol V represents unified mass.

Question 3.
Write the chemical symbols and Latin names of
(i) gold
(ii) mercury ?
Answer:
(i) Au (Aurum)
(ii) Hg (Hydrargyrum).

Question 4.
Are the mass of a molecule of a substance and its molar mass same ?
Answer:
No, they are different.

Question 5.
How are mass, molar mass and number of moles of a substance related to each other ?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 14

Question 6.
Avogardo’s number represents how many particles ?
Answer:
Avogadro’s number (Ng) represents 6.022 x 1023 particles.

Question 7.
Give an example of
(i) a divalent anion
(ii) a trivalent cation
(iii) a monovalent anion.
Answer:
(i) (SO4)2-
(ii) Al3+
(iii) Cl

Question 8.
Calculate the molar mass of ethyl alcohol (C2H5OH).
Answer:
Molar mass of C2H5OH= (2 x gram atomic mass of C) + (6 x gram atomic mass of H)
+ (1 x Atomic mass of O)
= (2 x 12 g) + (6 x 1 g) + (1 x 16 g) = 46 g.

Question 9.
If one mole of oxygen atoms weigh 16 grams, calculate the mass of one atom of oxygen (in grams).
(CBSE 2014)
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 15

Question 10.
What is the valency of calcium in CaCO3 ?
Answer:
The valency of Ca in CaCO3 is 2+ (i.e. Ca2+).

Question 11.
What happens to an element ‘A’ if its atom gains two electrons ?
Answer:
It changes to a divalent anion (A2-).

Question 12.
Why is a cation so named ?
Answer:
When electric current is passed through the solution of a salt like sodium chloride (NaCl), the positive ion (Na+) migrates towards cathode (negative electrode). It is therefore, called cation. Please remember that
• Positive ion migrating towards cathode on passing electric current is known as cation.
• Negative ion migrating towards anode on passing electric current is known as anion.

Question 13.
An element Z forms an oxide with formula Z2O3. What is its valency ?
Answer:
The valency of the element Z in Z2O3 is 3+.

Question 14.
The valency of an element A is 4. Write the formula of its oxide.
Answer:
The formula of the oxide is A2O4 or AO2.

Question 15.
An element X has valency 3 while the element Y has valency 2. Write the formula of the compound between X and Y.
Answer:
The formula of the compound between X and Y is X2Y3.

Question 16.
Formula of the carbonate of a metal M is M2CO3. Write the fomula of its chloride.
Answer:
The valency of the metal (M) in M2CO3 is (1+) i.e. metal exists as M+ ion. Therefore, the formula of metal chloride is MCl.

Question 17.
What do you understand from the statement “relative atomic mass of sulphur is 32”. (CBSE 2012)
Answer:
This means that an atom of sulphur is 32 times heavier as compared to 1/12 of the mass of 1 atom of C — 12(1 u).

Question 18.
Calculate the formula unit mass of CaCl2.
Answer:
Formula unit mass of CaCl2 (Calcium chloride)
= (1 x Atomic mass of Ca) + (2 x Atomic mass of Cl)
= (1 x 40 u) + (2 x 35.5 u) = 111 u.

Question 19.
Which of the following represents the correct chemical formula ?
(a) NaSO4
(b) CaPO4
(c) ZnS
(d) AlSO4.
Answer:
The formula (c) represents the correct formula. Both the ions are divalent i.e. Zn2+ and S2-. The name of the compound is zinc sulphide.

Question 20.
Sample A contains one gram molecules of oxygen molecules and sample B contains one mole of oxygen molecules. What is the ratio of the number of molecules in both the sample ?
Answer:
One gram molecules and one gram mole contain the same number of molecules (6.022 x 1023). Therefore, the ratio is 1 : 1.

Question 21.
Gram molecular mass of ammonia (NH3) is 17 g. Is it correct to regard it as formula unit mass also ?
Answer:
No, it is not correct. Ammonia exists in molecular form and is not an ionic compound made up of cation and anion. Therefore, it cannot have formula unit mass. It has only molecular mass.

Question 22.
Give one example each of polyatomic element and polyatomic ion.
Answer:
Polyatomic element (P4) ; Polyatomic ion (SO42-).

Question 23.
Name the element which is used as a reference for the atomic masses of the elements.
Answer:
1/12 of the mass of carbon atom taken as 12 u is used as a reference for the atomic masses of the elements.

Question 24.
Four samples of water [H2O] are collected from different sources. Each sample on analysis was found to contain same percentage of oxygen. Which law of chemical combination is demonstrated by the above observation ?
(CBSE 2014)
Answer:
The law of constant combination is demonstrated by this observation.

SHORT ANSWER QUESTIONS

Question 25.
List the elements present in
(i) quick lime
(ii) sodium hydrogen carbonate.
Answer:
(i) The chemical name of quick lime is calcium oxide. Its chemical formula is CaO. Elements present are Ca and O.
(ii) The chemical formula of sodium hydrogen carbonate is NaHCO3. The elements present are Na, H, C and O.

Question 26.
Cenvert into moles :
(i) 20 g of water
(ii) 20 g of carbon dioxide
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 16

Question 27.
(a) How many moles are present in 11.5 g of sodium ?
(b) The mass of an atom of element (X) is 2.0 x 10-23 g. Calculate its atomic mass.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 17

Question 28.
(a) How many particles are represented by 0.25 mole of an element ?
(b) Out of 4 g of methane (CH4) and llg of CO2, which has more molecules ?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 18

Question 29.
What is the number of molecules present in 1.5 mole of ammonia (NH3) ?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 19

Question 30.
Write the chemical symbols of two elements
(a) Which are formed from the first letter of the elements name.
(b) Whose name has been taken from the names of the elements in Latin.
Answer:
(a) Boron (B), carbon (C)
(b) Argentum (Ag), Kalium (K).

Question 31.
(a) Four samples of carbon dioxide (CO2) were prepared by using different methods. Each sample on analysis was found to contain 27.27% carbon by mass. Name the law which is in agreement with this observation.
(b) Explain why the number of atoms in one mole of hydrogen gas is double the number of atoms in one mole of helium gas.
Answer:
(a) Carbon dioxide consists of elements carbon and oxygen. Since the percentage of carbon in each sample is fixed, that of oxygen must be also fixed. This is according to law of constant proportions.
(b) Hydrogen gas is diatomic in nature (H2) while helium gas is monoatomic (He). As a result, the number of atoms in one mole of hydrogen. (2 x NA) are expected to be double as compared to number of atoms in one mole of helium (NA).

Question 32.
1022 atoms of an element ‘X’ are found to have a mass of 930 mg. Calculate the molar mass of the element ‘X’?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 20

Question 33.
(a) If the valency of carbon is 4 and that of sulphur is 2, write the formula of the compound formed between carbon and sulphur atoms. Also name the compound.
(b) What is wrong with the statement T mole of hydrogen ?
Answer:
(a) The formula of compound can be written by exchanging the valencies (cross-over). Therefore, the expected formula is C2S4 or CS2. The compound is called carbon disulphide.
(b) The statement is not correct. We must always write whether hydrogen is in atomic form or molecular form. The correct statement is :

Question 34.
T mole of hydrogen atoms or one mole of hydrogen molecules.
Identify the cations and anions in the following compounds :
(a) CH3COONa
(b) NH3
(c) NH4Cl
(d) SrCl2.
Answer:
(a) CH3COO, Na+
(b) It is a molecular compound
(c) NH4+ ,Cl (d) Sr2+, 2Cl

Question 35.
Classify the following based on atomicity
(a) O3
(b) P4
(c) S8. (CBSE 2012)
Answer:
Atomicity is the number of atoms present in one molecule of an element. Based upon this, the atomicity of different molecules may be expressed as :
(a) 3
(b) 4
(c) 8.

Question 36.
Give the formulae of the compounds that will be formed from the following sets of elements.
(a) Calcium and fluorine
(b) Magnesium and oxygen
(c) Sodium and sulphur
(d) Carbon and chlorine
(e) Carbon and sulphur
(f) Nitrogen and hydrogen.
Answer:
(a) CaF2
(b) MgO
(c) Na2S
(d) CCl4
(e) CS2
(f) NH3.

Question 37.
Which of the following symbols of elements are incorrect. Write correct symbols
(a) Iron (Ir)
(b) Gold (Au)
(c) Manganese (M)
(d) Potassium (Po)
(e) Zinc (ZN)
(f) Calcium (Ca).
Answer:
(a) Iron (Fe)
(c) Manganese (Mn)
(d) Potassium (K)
(e) Zinc (Zn).

Question 38.
Verify by calculation that :
4 moles of CO2 and 6 moles of H2O do not have same mass in grams.
Answer:
Molar mass of CO2 = 12 + 2 x 16 = 44 g
1 mole of CO2 has mass = 44 g
4 moles of CO2
have mass = 44 x 4 = 176 g
Molar mass of H2O = 2 x 1 + 16 =18 g
1 mole of H2O has mass = 18 g
6 moles of H2O have mass = 6 x 18 = 108 g.
This shows that these have different masses in grams.

Question 39.
A sample of vitamin C contains 2.48 x 1025 oxygen atoms. How many moles of oxygen atoms are present in the sample ?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 21

Question 40.
Calculate the total number of ions in 0.585 g of sodium chloride.
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 22

Question 41.
A flask contains 4.4 g of CO2 gas. Calculate
(a) How many moles of CO2 gas does it contain ?
(b) How many molecules of CO2 gas are present in the sample.
(c) How many atoms of oxygen are present in the given sample.
(Atomic mass of C = 12 u. O = 16 u)
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 23

Question 42.
Determine the molecular mass of :
(i) NH4OH
(ii) K2CO3
(iii) CH3COOH Given atomic masses :
H = 1.0 u ; O = 16.0 u ; C = 12.0 ; K = 39.0 u ; N = 14.0 u
Answer:
(i) Molecular mass of NH4OH
= Atomic mass of N + 5 x (Atomic mass of H) + Atomic mass of O
= 14 + 5 x 1 + 16 = 14 + 5 + 16 = 35 u
(ii) Molecular mass of K2CO3
= 2 x (Atomic mass of K) + Atomic mass of C + 3 x (Atomic mass of O)
= 2 x 39 + 12 + 3 x 16 = 138 u
(iii) Molecular mass of CH3COOH
= 2 x (Atomic mass of C) + 4 x (Atomic mass of H) + 2 x (Atomic mass of O)
= 2 x 12 + 4 x 1+2 x 16 = 60 u

Question 43.
(a) What is Avogadro Constant ?
(b) Calculate the number of particles present in 56 g of N2 molecule.
Answer:
(a) Avogadro’s number is the number of particles (atoms, ions, molecules etc.) present in one mole of any substance. It is denoted either as NA or as NQ. The number is also called Avogadro’s constant because its value is fixed (6.022 x 1023) irrespective of the nature of the particles.
(b) Molar mass of N2 = 14 x 2 = 28 g
28 g of N2 have molecules or particles = NA = 6.022 x 1023
56 g of N2 have molecules or particles = NA = 6.022 x 1023 x 2 = 1.204 x 1024

Question 44.
(a) An element ‘X’ exhibits variable valencies 3 and 5. Write the formulae of the chlorides of the element.
(b) What is the ratio by mass of the elements present in the chemical formula of magnesium oxide.
Answer:
(a) The formulae of the chlorides of the element ‘X’ = XCl5 and XCl3.
(b) The chemical formula of magnesium oxide is MgO. The elements are present in the ratio of 24 : 16 or 3 : 2.

Question 45.
Give the example of trivalent cation and monovalent anion. Write the formula of the compound formed by their combination. .
Answer:
Trivalent cation : Al3+ ; Monovalent anion : Cl
Formula of the compound : AlCl3.

Question 46.
(a) State the law of conservation of mass
(b) What mass of silver nitrate will react with 5.85 g of sodium chloride to produce 14.35 g of silver chloride and 8.5 g of sodium nitrate if the law of conservation of mass is true ?
Answer:
(a) The total mass of the products in a physical change or a chemical reaction is equal to the total mass of the reactants that have combined. The law may also be stated in another form. The mass can neither he created nor destroyed in a physical change or a chemical reaction.
(b) The chemical reaction leading to products is :
Mass of reactants = x g + 5.85 g Mass of products = 14.35 g + 8.5 g According to law of conservation of mass
Mass of reactants = Mass of products . (x + 5.85) g = (14.35 + 8.5) g
x = (22.85 – 5.85) g = 17.0 g

LONG ANSWER QUESTIONS

Question 47.
(a) The mass of one molecule of a substance is 4.65 x 10-23 g. What is its molecular mass ? What could this substance be ?
(b) Which have more molecules? 10 g of sulphur dioxide (SO2) or 10 g of oxygen (O2) ?
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 24
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 25

Question 48.
Which has more atoms ?
(a) 10 g of nitrogen (N2)
(b) 10 g of ammonia (NH3)
Answer:
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 26

Question 49.
(a) Explain with the help of a labelled diagram an activity for the verification of law of conservation of mass.
(b) Find the number of atoms present in 100 g of sodium and 100 g of iron. (Given that Na = 23 u ; Fe = 56 u ;
Answer:
(a) The total mass of the products in a physical change or a chemical reaction is equal to the total mass of the reactants that have combined. The law may also be stated in another form. The mass can neither he created nor destroyed in a physical change or a chemical reaction.
In other words, the mass remains unchanged or conserved in a chemical reaction. The law is also known as the Law of Indestructibility of Matter.
Explanation : Let us try to analyse as to what happens in a chemical reaction. To understand the same, let us consider a chemical reaction between barium chloride and sodium sulphate. When the solutions of these reactants prepared separately in water are mixed, the following chemical reaction takes place :
Barium chloride + Sodium sulphate———– > Barium sulphate + Sodium chloride (white precipitate)
If we look at this reaction, we find that the exchange of constituents has taken place between the reactants, i.e. chloride part of barium chloride has been exchanged by sulphate part of sodium sulphate. As such, no loss or gain in mass is expected. In other words, the mass remains conserved or does not change.
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 27
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 28

Question 50.
(a) Give one point of difference between an atom and an ion.
(b) Give one example each of a polyatomic cation and a polyatomic anion.
(c) Identify the correct chemical name of FeSO4 from the given names Ferrous sulphate, Ferrous sulphide, Ferrous sulphite.
(d) Write the chemical formula for the chloride of magnesium.
Answer:
(a) An atom is always neutral in the sense that it does not carry any charge. An ion carries either positive charge (cation) or negative charge (anion).
(b) Ammonium (NH4)+ ion is a polyatomic cation while sulphate (SO4)2- ion is a polyatomic anion.
(c) Correct chemical name of FeSO4 is ferrous sulphite.
(d) Chemical formula for the chloride of magnesium is MgCl2.

Question 51.
(a) What do the following observations stand for ?
(i) 2O
(ii) 3O2
(b) Which amongst the following has more number of atoms and how much ?
(i) 11.5 g of sodium
(ii) 15.0 g of calcium
Answer:
(a) (i) 2O represent two atoms of oxygen (or the gram atoms of oxygen
(ii) 3O2 represent three molecules of oxygen or three gram moles of oxygen.
NCERT Solutions For Class 9 Science Chapter 3 Atoms and Molecules 29

NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules

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Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur

Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur

Check the below Online Education NCERT MCQ Questions for Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur with Answers Pdf free download. https://ncertmcq.com/extra-questions-for-class-9-social-science/

Online Education for The Story of Village Palampur Class 9 Extra Questions Economics Chapter 1

Class 9 Economics Chapter 1 Extra Questions And Answers Question 1.
What are the different types of production activities in the village?
Answer:
There are two types of production activities in the village-

  1. farming and,
  2. non-farm activities. The non-farm activities include small manufacturing, transport and shop-keeping.

Class 9 Economics Chapter 1 Extra Questions Question 2.
Define factors of production.
Answer:
The various inputs required to produce goods and services are called as factors of production. There are mainly four factors of production: land, labour,’ physical capital and human capital.

Class 9 Economics Chapter 1 Short Question Answers Question 3.
Distinguish between fixed capital and working capital.
Answer:
The physical capital which can be used in production over many years is called as fixed capital. For example: tools, machines and buildings. On the other hand, the physical capital which gets completely used up during the production process is called as working capital. For example: raw materials and money in hand.

Economics Class 9 Chapter 1 Extra Questions Question 4.
What is human capital?
Answer:
The knowledge and enterprise required to put together land, labour and physical capital to produce an output either for self-consumption or for sale in the market is called as human capital.

Ncert Class 9 Economics Chapter 1 Important Questions Question 5.
Define multiple cropping.
Answer:
To grow more than one crop on a piece of land during the year is known as multiple cropping. It is the most common way of increasing production on a given piece of land.

Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur

Ncert Solutions For Class 9 Economics Chapter 1 Extra Questions Question 6.
Mention tire two ways of increasing production from the same land.
Answer:
The two ways of increasing production from the same land are:

  1. Multiple cropping and
  2. Using modern farming methods.

Extra Questions For Class 9 Economics Chapter 1 Question 7.
What is the working capital required by the farmer using modern farming methods?
Answer:
The working capital required by the farmer using modem farming methods is HYV seeds, chemical fertilizers and pesticides.

Class 9 Economics Ch 1 Extra Questions Question 8.
What is surplus?
Answer:
The produce left over after self-consumption is called as surplus. This surplus is brought Over to the market for sale.

Economics Chapter 1 Class 9 Extra Questions Question 9.
Briefly explain the four factors of production.
Answer:
Every production is organized by combining land, labour, physical capital and human capital which are known as factors of production.

These factors are explained below:

  • Land-If is the first requirement for production of goods and services. The land required for farm activities is practically fixed.
  • Labour- The second requirement is labour i.e. people who will do the work. Some activities require highly educated workers like banking and some require workers, for manual work, for example, carpenter.
  • Physical capital-Physical capital es the variety of inputs required at every stage dur¬ing production. For example: tools, building, raw materials etc. Physical capital is of two types: fixed capital and working capital.
  • Human capital-The knowledge and enterprise required to put together land, labour and physical capital for producing an output either for self-consumption or to sell in the market is called, as human cap.

The Story Of Village Palampur Class 9 Extra Questions Question 10.
What is the main constraint on land?
Answer:
In villages, farming is the main production activity. Most of the people are dependent on fanning for their livelihood. The well being of these people is closely related to production in the farms. The farm production depends upon the land area under cultivation. But there is one constraint on it.

Land area under cultivation is practically fixed. There has been no expansion in land area under cultivation since 1960. By then, some of the wastelands in the village had been converted to cultivable land. There exists no further scope to increase farm production by bringing new land under cultivation.

Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur

Class 9 Economics Chapter 1 Worksheet With Answers Question 11.
What is multiple cropping? Explain by giving an example.
Answer:
To grow more than one crop on a piece of land during the year is known as multiple cropping. It is the most common way of increasing production. During different seasons different crops are grown on the same piece of land.

The farmers are able to grow

  • Land-It is the first requirement and natural resource. Land is a scarce resource in case of farm activities. Therefore, it must be properly utilised.
  • Labour-The second requirement is labour. By labour we mean people who will » do the work. Some production activities require highly skilled and educated workers to perform tire necessary task. Other activities require workers who can do manual work. Each worker is providing the labour necessary for production.
  • Physical capital-It is the third requirement. Physical capital means the variety of inputs required at every stage during production.

The items that come under physical capital are:

  1. Tools, machines and buildings- Tools, machines and buildings can be used in production over many years, and are called as fixed capital.
  2. Raw materials and money in hand- Production requires a variety of raw materials such as the yarn used by weaver and the clay used by the potter. Also, some money is always required during production to make some payments and buy other necessary items. Raw materials and money in hand are called working capital.

Human capital-The fourth requirement of production is human capital. The knowledge and enterprise required to put together land, labour and physical capital to produce an output either for self-consumption or for sale in the market is called as human capital.

Class 9 Economics Chapter 1 Extra Questions Very Short Question 14.
Write a short note on green revolution.
Answer:
The green revolution started in India in the late 1960’s It introduced the Indian farmer to cultivation of wheat and rice using high yielding varieties of seeds (HYV). These seeds give much greater amounts of grain on a Single plant as compared to traditional seeds.

As a result the same piece of land would now produce for larger quantities of foodgrains ‘than was possible earlier. HYV seeds, however, needed plenty of water, chemical fertilizers and pesticides to produce best results.

Higher yields were possible only from a combination. of HYV seeds, irrigation, chemical fertilisers, pesticides etc. Farmers of Punjab, Haryana and Uttar Pradesh were the first to try out the modem farming method in India. The farmers in these regions set up tube wells for irrigation and made use of HYV seeds, chemical fertilisers and pesticides. Some of them also bought farm machineries like tractors and threshers. They were rewarded with high yields of wheat.

But green revolution did not come without negative effects. Scientific reports indicated that modern farming methods have overused the natural resource base. In many areas there was loss of soil fertility due to increased use of chemical fertilizers. The continuous use of groundwater for tubewell irrigation has reduced the wafer table below the ground. This is a huge loss. Therefore, one must take care of the environment to ensure future development of agriculture.

Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur

The Story Of Village Palampur Extra Questions Question 15.
How do fanners arrange for the capital needed in fanning?
Answer:
Modem farming methods require a great deal of capital, therefore farmers now need more money than before. Different farmers have different source of capital. Most of the small farmers borrow money from large farmers or the village money-lenders or the traders who supply various inputs for cultivation. The rate of interest on such loans is very high. They are put to great distress to repay the loan. Sometimes the small farmers have to work on the fields of medium and large farmers at very low wages to repay the loan. .

In contrast to small farmers, the medium and large farmers have their own savings from farming. These farmers sell their surplus produce in market and get good, earnings. A part of these earnings are saved and kept for buying capital for the next season. Thus, they are able to arrange for the capital for farming from their own savings.

The Story Of Village Palampur Important Questions Question 16.
What is the condition of non-farm sector in villages? How can these activities Be increased?
Answer:
The non-farm activities include small manufacturing, transport shop-keeping etc. At present, the non-farm sector in the village is not very large. Out of every 100 workers in the rural areas in, India, only 24 are engaged in non-farm activities. Though there is a Variety of non-farm activities in the village, the number of people employed in each is quite small.

Unlike farming, non-farm activities require little land. People with some amount of capital can set up non-farm activities. The capital required can be mobilised either from one’s own savings or by taking a loan. It is important that loan be available at low rate of interest so that even people without savings can start some non-farm activities.

Another thing which is essential for non-farm activities is to have market where the goods and services can be sold. As more villages get connected to towns and cities through good roads, transport and telephone, it is possible that the opportunities for non-farm activities production in the village would increase in the coming years.

Class 9 Economics Chapter 1 Extra Questions and Answers The Story of Village Palampur

Ch 1 Economics Class 9 Extra Questions Question 17.
How are three factors of production land, labour and capital used in farming?
Answer:
Among these factors of production, labour is the most abundant factor of production. There are many people who are willing to work as farm labourers in the villages whereas the opportunities of work are limited. They belong to either landless families or small farmers They are paid low wages and lead a difficult life.

In contrast to labour, land is a scarce factor of production. Land has been used to its maximum. There can be no expansion in cultivated land area. Moreover, even the existing land is distributed unequally among the people engaged in farming. There are large number of small farmers who cultivate small plots of land and live in conditions not much better than the landless farm labourers. To make the maximum use of the land farmers use multiple cropping and modem methods of farming both these have led to increase in production of crops.

Modern farming methods require a great deal of capital. Small farmers usually need to borrow money to arrange for the capital and are put to great distress to repay the loan. Therefore, capital to is a scarce factor of production, particularly for the small farmers.

Though both land and capital are scarce, there is a basic difference between the two factors of production. Land is a natural resource whereas capital is man-made. It is possible to increase capital, whereas land is fixed. Therefore, it is very important that we take good care of land and other natural resources used in farming.

Extra Questions for Class 9 Social Science

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

Online Education for Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

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Online Education for Constitutional Design Class 9 Extra Questions Civics Chapter 3

Question 1.
Mention the number of states in the Union of India.
Answer:
Twenty eight (2006).

Question 2.
Mention the number of union territories in India.
Answer:
Seven (2006).

Question 3.
Give the dafe when the Constitution of India was Enforced.
Answer:
January 26, 1950, also called the Republic Day.

Question 4.
Who was elected as the President of the Constituent Assembly ?
Answer:
Dr. Rajendra Prasad.

Question 5.
Name the chairman of the drafting committee who drafted the constitution.
Answer:
Dr. B. R. Ambedkar.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

Question 6.
Name the three states which Originated in 2001..
Answer:

  1. Chattisgarh,
  2. Uttranchal,
  3. Jharkhand.

Question 7.
What is meant by the union territory?
Answer:
Union territory is the region where the government is under the direct control of the Centre.

Question 8.
For how many days did the Constituent Assembly meet?
Answer:
114 days.

Question 9.
What time was taken in the making of the constitution?
Answer:
2 years 11 months and 18 days.

Question 10.
Why tire Constitution is called a living document?
Answer:
The Constitution is called a living document because it has the scope of continuous development according to the needs, aspirations and the expectations of the people.

Question 11.
Name the countries from where the Constitution had incorporated some of the salient features.
Answer:

  • England,
  • Ireland,
  • France.
  • U.S.A
  • Australia.

Question 12.
Who set out the underlying philosophy of the Constitution?
Answer:
Jawaharlal Nehru.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

Question 13.
What is highlighted by the Preamble?
Answer:
The Preamble highlights the fundamental and noblest values and guiding principles on which the Indian Constitution is based.

Question 14.
How many items are there in the Concurrent List ?
Answer:
47.

Question 15.
How many items are there in the State List?
Answer:
66.

Question 16.
Which one of the three lists has Tnaximum of the items?
Answer:
The Union List.

Question 17.
How many subjects are there in the Union List ?
Answer:
97.

Question 18.
Which kind of citizenship has been provided in India?
Answer:
Single citizenship.

Question 19.
What are the provisions made by the, Indian Constitution to cope with a situation which is not normal?
Answer:
Emergency provisions.

Question 20.
By whom the residuary powers are enjoyed?
Answer:
By the Central Government.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

Question 21.
In which of the lists the subjects like criminal and civil procedure are included?
Answer:
In the Concurrent List.

Question 22.
Name some of the subjects included in the Union List.
Answer:

  • Banking,
  • Telegraph,
  • Defence,
  • Foreign affairs,
  • Atomic Energy etc.

Question 23.
Name some of the subjects included in the State List.
Answer:

  • Police,
  • Local government,
  • Agriculture,
  • Trade and commerce etc.

Question 24.
At the time of emergency which one of the governments has been more powers?
Answer:
The Central Government.

Question 25.
How were the number of seats allocated to the states?
Answer:
Each of the states was allocated the number of seats in such a manner that the ratio between the number of seats and the population remain practical.

Question 26.
What is Constitution?
Answer:
Constitution is a set of rules according to which the government of a country runs. The constitution also defines the composition and powers of the three organs of the government- the Executive, the Legislative and the Judiciary.

The constitution also explains the relations between the government are the citizens. The constitution defines the powers of the government so clearly that in order to make sure the government does not misuse its powers. The constitution protects the right of the citizens. In fact, every independent country prepares a constitution of its own as it signifies independence.

Question 27.
Explain in your own words the difference you find between the political maps of India, in 1947 and in 2002.
Answer:
The political map of India in 1947:
In 1947, when India got its freedom; it had provinces and several princely states. Many of its parts were still: under the foreign possession like Pondicherry, Yanam, Mahe, and Chandernagore were under the French rule while Goa, Daman and Diu were under the rule of Portugal, This also shows nearly 562 princely states independence. Hie political map of India in 2002: This map shows the present political condition of India. having 28 states and 7 union territories. In the present map of India, there is no foreign territory.

Question 28.
Why the Constituent Assembly is called the miniature India?
Answer:
The Constituent Assembly is called the miniature India because the members of the Constituent Assembly were from all of the parts and communities of the country. In fact, the Constituent Assembly did not only have the members from different communities and regions but also had the members representing different political parties. Hence, it was a miniature India in a very true sense.

Question 29.
Give a brief description of the Constituent Assembly.
Answer:
The Constituent Assembly had the great leaders like Pt. Jawaharlal Nehru, Sardar Ballabhbhai Patel, Maulana Abdul Kalam Azad, Dr.Shyama Prasad Mukerji, Sardar Baldev Singh. Dr. Rajendra Prasad was the President of the Constituent Assembly. Dr. B.R. Ambedkar was the Chairman of the Drafting Committee.

In fact, the Constituent Assembly had its members from different regions and sections of India. More than 30 members were from scheduled castes. The Anglo Indian community was being represented by Frank Anthony while H. P. Modi was representing the Parsi community.

Question 30.
Make a table of the languages which have been included in the Constitution.
Answer:
Assemse Bengali Gujarati’ Hindi Dogri Kannada Kashmiri Konkani Malayalam
Manipuri Marathi Nepali Orissa Santhali
Punjabi Sanskrit Sindhi Tamil Maithali
Telugu Urdu Bodo

Question 31.
Name the states which were carved out of in view of the popular demand much after 1956.
Answer:
In 1956 the states of India were reorganized for the first. But several states were carved out in view of the popular demands.

These states are

  • Gujarat,
  • Nagaland,
  • Haryana,
  • Mizoram,
  • Himachal Pradesh,
  • Manipur,
  • Meghalaya,
  • Arunachal Pradesh,
  • Tripura,
  • Goa,
  • Chhattisgarh,
  • Jharkhand,
  • Uttaranchal.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

Question 32.
How many members were there in the Indian constituent Assembly in December 1947?
Answer:
In December 1947 the Constituent Assembly of India had 299 members. 229 members among them were from the Indian states while 70 members were from the princely states.

Question 33.
Why has Hindi been adopted as the official language of the Union government?
Answer:
After the independence, the need of adopting an Indian language to replace English was felt.

The Constituent Assembly choose Hindi to replace English because of the following reasons:

  • Of all the Ind.ian languages, Hindi is spoken by a large number of the people. ‘
  • Hindi is understood by a large number of people.
  • Even the persons whose mother tongue is not Hindi can understand Hindi.

“Because of these plus points, Hindi has been adopted as the official language of the Union government.
However, an assurance was also given that so long as it is found necessary the non- Hindi speaking states have been given the liberty to use English along with Hindi.

Question 34.
What was the need of reorganization of the states after the independence?
Answer:
Soon after the independence, most of the princely states and the states were joined together so that the unity and the integration of the country would be maintained. But after some time the need was felt to reorganise the states because of the expectations and aspirations of the people and also because of their demands.

Question 35.
Why is Preamble very important?
Answer:
The Preamble contains the ideals and basic principles of the Indian constitution. The Preamble is riot a part of the constitution. The Preamble is neither enforceable in a court of law. No one has the right to go to the court and say that the. Preamble has not been enforced by the government.

Yet the Preamble is, very important as it serves as the guiding light of the constitution. The Preamble of the Indian constitution makes it absolutely clear that the Indian constitution stands for justice, Liberty, Equality and Fraternity.

Question 36.
What do you know about the Universal Adult Franchise? Why the constitution of India has adopted it?
Answer:
The term Universal Adult Franchise is meant by the voting right of the citizen. In India, every citizen who has completed the age of 18 years is able to participate in the election procedure.

This right has been extended to all the citizens irrespective of. their caste, creed, colour, religion, sex or status. Our Constitution has adopted this system to make India a real democracy. In a very true sense, this feature has made India the largest democracy in the world.

Question 37.
Write down the four ideals on what the Preamble of the of India emphasises. *
Answer:
The preamble of our constitution emphasises on the following four elements-

  1. Justice-According to the Preamble every citizen must get justice in every sector including social, economic and political sectors.
  2. Liberty-Each Indian must have the liberty of thought, expression, belief, faith and worship.
  3. Equality-The Preamble ensures equality of status and opportunity for all the citizens.
  4. Fraternity-It assures the dignity of the individuals and the unity and integrity of the Nation.

Question 38.
Explain clearly the meaning given to secularism.
Answer:
Secularism in India acquired a meaning different from the way it is. understood in the West. It means respect for all religious beliefs and practices, regardless of who and what number follow a particular religion. It also means that individual has complete freedom of faith and worship.

Question 39.
Explain as to how the European countries and India got their democratic rights.
Answer:
In Europe, people won democratic rights through long struggles against, the privileges of aristocrats and powers of monarchs. Sometimes, these struggles were highly violent. For example, during the French Revolution, hundreds of supporters of monarchy were killed.

In India, the struggle for democracy was carried on against the British colonial rule. It retrained by and large peaceful. With the adoption of the Constitution, all basic democratic political rights along with universal adult suffrage were introduced in India at one stroke.

Question 40.
What is the basic structure of the T Constitution?
Answer:
The Constitution of India does not describe as what is the basic structure of the Constitution. But the Supreme Court has done it.

The basic structure of the constitution is as follows:
“every provision of the Constitution is essential; otherwise it would not have been put in the Constitution. This is true. But this does not place every provision of the Constitution in the same position. The true position is that every provision of the Constitution can be amended provided the basic foundation and structure of the Constitution remains the same.

The basic structure may be said to consist of the following features:

  • Supremacy of the Constitution;
  • Republican and Democratic form of Government;
  • Secular character of the Constitution;
  • Separation of powers between the legislature, the executive and the judiciary;
  • Federal character of the Constitution.”

“The above structure is built on the basic foundation, i.e., the dignity and freedom of the individual. This is of supreme importance. This cannot, by any form of amendment, be destroyed,” The Supreme Court said this in its judgement on the Kesavananda Bharati case.

Question 41.
Explain terms such as “sovereign’, ‘democratic’, and republic.
Answer:
The Constitution proclaimed India to be a sovereign democratic republic. This three words-sovereign, democratic and republic are significant. Sovereignty means supreme power. It means the right of people to take decisions on internal matters as well as policies determining our relations with other countries. As the authority of the government rests upon the support of the people, people are sovereign. Democracy means people enjoy equal political rights.

They include right to form associations, right to criticise and oppose policies of government, right to contest elections and hold public offices. People have a right to elect a government through periodical, free and fair elections. Government is responsible to people and exercises powers only as defined in the Constitution.

No government can continue in power without the support of majority of people’s representatives in the legislature. People can change the government in elections. Republic means that the head of the State (President) is an elected person. He/ she wields power for a fixed term. India is a Union of States.

Question 42.
Compare the grant of the democratic rights as it came in the European countries and in India.
Answer:
European countries had developed industrially before they became full-fledged democracies. But in India democracy came before any such substantial industrial development. At the time of its Independence, India was predominantly an agrarian economy. Illiteracy was widespread. Poverty was rampant. This was an unusual experiment in establishing democracy in conditions of mass poverty. European countries had become strong nations by the time they became democratic.

The situation was different in. our country. The task of building the nation in real sense started after we became a democracy. In Europe and America expansion of democracy took place by limiting the powers of government. People there believed that freedom is possible if there is no unnecessary interference of government in private affairs of the individual.

So they fought for freedoms against absolutist governments. But in India, government was assigned a larger role from the beginning: We wanted the state to bring about all-around development. So the expansion of democracy in India has been bound with the expansion of government.

Thus in the history of the Western nations, expansion of democracy was associated with industrialisation, emergence of strong nations, militant struggles for voting rights and limiting the governmental powers. Those countries went through these stages one after the other, over a period of nearly 200 years. But in India democracy had to address these issues all at the same time.

The country has to industrially develop, build a nation and national government, transform social relations, and meet the basic needs of the people. The Indian state had to simultaneously pursue these, goals in a democratic framework.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

Question 43.
Write a brief note on the Directive Principles of State Policy.
Answer:
The Constitution prescribed certain guidelines for governments in making policies. These are called “Directive Policies of State Policy”. Their objective is to secure a social order, which promotes the welfare of the people. For example, the State should take steps for securing an adequate means of livelihood to all citizens.

The ownership and control of the material resources of the nation are to be distributed in such a way as to secure the common good. The economic system of the county is to be operated in a maimer so as to prevent concentration of wealth.

Men and women shall receive equal pay for equal work. Free and compulsory education, shall be provided to all children. Child labour shall be eliminated. The principles of socialism and. Gandhian ideals are incorporated in these Directive Principles.

Question 44.
Who proposed the Objectives Resolution? For what did it stand?
Answer:
The Objectives Resolution was proposed by Pt Jawaharlal Nehru on 13th December 1946. It was passed on 22 January 1947. Objective Resolution was in fact a document which contained the main objectives of the framing of the new constitution for India.

The Objectives Resolution stood for the. following objectives-

  • The Objectives Resolution dealt with fundamentals which were commonly held and had been accepted by the people.
  • The Resolution states that it is our firm and solemn resolve to have a sovereign republic.
  • It stands for a free India that can be nothing but a republic.
  • It declared that the Union would be an “independent Sovereign Republic” and it would be comprised of the autonomic units of the British and the princely states with residuary powers.
  • It ensures that the ideas of social, political and economic democracy would be guaranteed to all the sections of the people.
  • It also ensures that an adequate safeguard would be provided for minorities and the backward communities and the areas.
  • It also guaranteed that the people of India would be given the freedom of thought, vocation, association, expression, belief, faith, worship and in law and morality.

Objective Type Questions

1. Fill up the following blanks with suitable words-

(i) The Constitution of our country has taken ……………………… years ……………………… months……………………… days in its making.
Answer:
2, 11,18.

(ii) In the Constituent Assembly, the Parsi community was being represented by ……………………… .
Answer:
H. P. Modi

(iii) In the Constituent Assembly, the total number of the members from the states of the British India were ……………………… .
Answer:
296

(iv) The Objective Resolution was proposed by ……………………… .
Answer:
Pt. Jawhar Lai Nehru.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

2. Put (✓) before the correct sentences and (✗) before incorrect ones.

(i) The Constituent Assembly was not directly elected by the people.
Answer:
(✓)

(ii) Shyama Prasad Mukerjee was not among the leaders who guided the discussion in the constituent Assembly.
Answer:
(✗)

(iii) Constitution is a fundamental legal document.
Answer:
(✓)

(iv) British India was an independent, Sovereign and Republic.
Answer:
(✗)

(v) The underlying philosophy of the constitution was set out by Jawaharlal Nehru in his Objective Resolution.
Answer:
(✓)

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

(vi) Yanam was possessed by France.
Answer:
(✓)

(vii) The Drafting committee was known as the miniature of India.
Answer:
(✗)

3. Choose the correct answer from the alternatives given here:

(i) The following was the President of the Constituent Assembly:
(a) Dr. Ambedkar
(b) Dr. Rajendra Prasad
(c) Gandhiji
(d) Nehru
Answer:
(b) Dr. Rajendra Prasad

(ii) The following was the chairman of the Constitution Drafting Committee:
(a) Dr. Ambedkar
(b) Dr. Rajdendra Prasad
(c) Gandhiji
(d) Nehru
Answer:
(a) Dr. Ambedkar.

(iii) India had enacted its Constitution on:
(a) 26th January 1930
(b) 26th November 1949
(c) 15th August 1947
(d) 26th January 1950.
Answer:
(d) 26th January 1950.

Class 9 Civics Chapter 3 Extra Questions and Answers Constitutional Design

(iv) India’s Constitution is:
(a) Flexible
(b) Rigid
(c) Partly flexible, partly rigid
(d) Neither flexible nor rigid.
Answer:
(c) Partly flexible, partly rigid

(v) India’s federating units are:
(a) 25
(b) 26
(c) 27
(d) 28
Answer:
(d) 28.

Extra Questions for Class 9 Social Science

The Dear Departed Extra Questions and Answers Class 10 English Literature

Online Education for The Dear Departed Extra Questions and Answers Class 10 English Literature

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Online Education for The Dear Departed Extra Questions and Answers Class 10 English Literature

The Dear Departed Extra Questions and Answers Short Answer Type

The Dear Departed Question Answer Question 1.
“Good gracious, that’s never them.” What does Amelia mean?
Answer:
Amelia’s father Abel Merryweather, who stays with her, has died. She wants to take a few things that belong to him for herself before her sister arrives. So she is worried that they may have come already.

The Dear Departed Part 1 Questions And Answers Question 2.
How did Mrs Slater plan to outshine the Jordans? What does it reveal about her character?
Answer:
Mrs Slater is dressed in black, but is not in complete mourning. She has got her husband to wear a black tailcoat, grey trousers, a black tie and a bowler hat. Victoria, her daughter, is wearing a white frock with a black sash. She feels she will outshine the Jordans as Ben and Elizabeth will not yet have thought about mourning.

The Dear Departed Lesson Questions And Answers Question 3.
Why does Mrs Slater decide to shift the bureau from grandfather’s room before the arrival of the Jordans? How does Henry react to the suggestion?
Answer:
Mrs Slater always wanted to have the bureau after grandfather died. She feels she can easily take it before . her sister arrives as it has been bought recently and her sister doesn’t know of it. She says if she leaves it in grandfather’s room, her sister will drive a hard bargain. Henry feels it is not sensitive or becoming to do that.

The Dear Departed Part 2 Questions And Answers Question 4.
“I suppose it’s in the family.” What does Henry mean by that?
Answer:
Amelia calls her sister Elizabeth heartless and insensitive. She also feels that as Elizabeth is selfish and greedy, she will soon arrive for her share of grandfather’s property. Henry implies that both the sisters are similar in nature.

The Dear Departed Part 1 Question And Answers Question 5.
“You must arrange with Elizabeth when you’re dividing things up.” What does this reveal of Henry’s character?
Answer:
This shows that Henry is fair. He does not want to cheat Elizabeth out of her fair share by grabbing things for himself. He feels it should be decided who is to take what, after Elizabeth arrives.

Dear Departed Questions And Answers Question 6.
Why wouldn’t Henry care to bring the bureau downstairs?
Answer:
Henry feels it is not delicate or sensitive to bring the bureau down. Abel Merryweather has just died and instead of mourning him, they were trying to grab his things?Moreover, he feels that it should be decided who is to take what, after Elizabeth arrives.

The Dear Departed Questions And Answers Question 7.
“Elizabeth could have that and welcome.” What does Amelia mean by that?
Answer:
Amelia plans to bring grandfather’s new bureau downstairs and put their own chest of drawers in grandfather’s room. This way Elizabeth will look upon it as her father’s property and lay claim to it. Amelia doesn’t mind letting go of it as it is old and shabby and she had always wanted to get rid of it.

The Dear Departed Question Bank Question 8.
What does Henry tell Victoria when she asks if they are pinching grandfather’s bureau?
Why does Henry want to hide the truth from Victoria? How does Mrs Slater handle the same situation?
Answer:
Henry tells Victoria that Grandpa had given it to her mother before he died. He does not want the sensitive young child to think poorly of her parents. So he wishes to hide the truth from her. On the other hand, Mrs Slater who is practical and brusque, tells Victoria to be quiet and not tell her aunt about it.

The Dear Departed Question Answer Degree Question 9.
“I thought I’d fetch this down as well.” What does Mrs Slater bring down? What does ‘as well’ mean in this context?
Answer:
Mrs Slater brought grandfather’s clock downstairs along with his bureau. In this context, ‘as well’ refers to the clock in addition to the bureau.

The Dear Departed 2 Questions And Answers Question 10.
What is the reason for the Jordans taking a long time to get to the house of the Slaters? What does it show about the two sisters’ attitude towards each other?
Answer:
The Jordans came late because they bought new mourning clothes and dressed up in them before reaching the Slaters’ residence. This shows that both the sisters were trying to get the better of each other all the time.

Dear Departed Comprehension Questions Question 11.
What does Mrs Jordan describe as ‘a fatal mistake’? What is the irony in the comment she makes on Mrs Slater’s defense?
Answer:
Mrs Jordan calls not calling in a doctor to see grandfather ‘a fatal mistake’ as the doctor may have saved Abel Merryweather’s life. It turns out that Abel Merryweather was alive. He realized his daughters were selfish and greedy and he decides to change his will.

Dear Departed 2 Comprehension Questions Question 12.
“Your father wasn’t drowned, Elizabeth.” Why does Henry say this?
Answer:
Elizabeth wanted to know why the Slaters had not called in a doctor to see their father when he was supposedly gone. She added that at times people who have been presumed dead were revived by doctors.
Henry tells her that such incidents have occurred only with people who drowned. Therefore, he states that Abel Merryweather had not died of drowning.

Question 13.
“If there was one thing he couldn’t bear it was water.” What does Ben mean by this joke? Whom is he talking about?
Answer:
Ben is talking about his father-in-law, Abel Merryweather. He implies that Abel did not wash as often as he should have and that he drank a lot. He did not drink water.

Question 14.
Ben appreciates grandfather saying “its’ a good thing he did.” Later he calls him a “drunken old beggar.” Why does he change his opinion about grandfather?
Answer:
Ben praises Abel Merryweather when he thinks that the old man has paid his insurance premium that morning and they will inherit his insurance money. But when Victoria Slater tells them that grandfather had not gone to pay the insurance premium that morning but had gone with his friend to the Ring-o’-Bells for drinks, Ben is angry and calls him a drunken old beggar as the insurance policy may have lapsed and there may be no money for them.

Question 15.
What amazing news does Victoria bring as she comes downstairs?
Answer:
Victoria brings the news that her grandfather was getting up and that she had seen him do so.

Question 16.
What makes grandfather ask, “What’s the matter with little Vicky?”
Answer:
As soon as Vicky saw grandfather get up, she was terrified and ran down. Abel Merryweather was puzzled to see his granddaughter run away from him in fear. That is why he asked that.

Question 17.
Why is Mrs Jordan disconcerted when Mrs Slater brings ir^the topic of the gold watch?
Answer:
Mrs Jordan claimed that grandfather had promised his gold watch to her son, Jimmy. She was disconcerted when Mrs Slater brings in the topic of the gold watch because she knew her lie would be out.

Question 18.
How does the truth about the bureau come out?
Answer:
Grandfather, talking about his condition, says he had been in a daze and not asleep. At that point, he recollects Amelia and Henry had come to his room and shifted his bureau out.

Question 19.
How does Amelia get even with her sister?
Answer:
When Elizabeth tries to convince her father to go and live with her, she tells Abel that she and her sister had quarrelled because Elizabeth had said she wouldn’t take him off their hands at any price. She adds that Elizabeth had said she had enough of him to last a lifetime, and the Slaters would have to keep him.

Question 20.
What change does Abel Merryweather plan to make in his new will? What effect does it have on his daughters?
Answer:
Abel Merryweather said that he will change his will, stating that his money and his bits of things would go to whomever he was living with when he died. His daughters at once began to fight as each wanted to keep him with her, while earlier they had fought over not wanting to keep him.

Question 21.
What were the three things grandfather planned to do on Monday next?
Answer:
On Monday next, grandfather planned to do three things. He planned to go to the lawyer’s and alter his will leaving all he had to the person he was staying with, at the time of his death. He also planned to go to the insurance office and pay his premium. The third thing was to go to St Philip’s Church and get married to Mrs John Shorrocks.

Question 22.
In what way is the play The Dear Departed a satirical comment on the nature of human beings?
Answer:
The play brings out the greed and selfishness of people for whom money is more important than relationships. They are more interested in what they will inherit and try to grab the lion’s share.

The Dear Departed Extra Questions and Answers Long Answer Type

Question 1.
Bring out the irony in the title of the play.
Answer:
The title The Dear Departed refers to the death of a loved one but Abel Merryweather is neither dearly loved nor departed. The daughters do not mourn his death. They wanted to grab whatever belongings they can after his death. He was not dead but merely drunk.

Question 2.
Write a character sketch of Mrs Slater.
Answer:
Mrs Slater is greedy and wants to take some of grandfather’s things she likes before her sister arrives. She is overbearing and gets the reluctant Henry to help her shift the bureau and also put on grandfather’s slippers. She is straight talking, rude and impolite to her sister. She lacks feelings and hurts grandfather by telling him that Elizabeth did not wish to keep him.

Question 3.
Write a character sketch of Mrs Jordan.
Answer:
Mrs Jordan is greedy and arrives to take her share of grandfather’s things though she had vowed never to enter the house. She is bothered by appearances and comes dressed in new mourning. She is overbearing and dominates Ben. She is rude and impolite to her sister and lacks feelings and hurts grandfather by telling him that Amelia had started stealing soon as she had realised he was no more.

Question 4.
How does the spat between his daughters lead to grandfather discovering the truth?
Answer:
He hears about the spat between his daughters when he gets up. Elizabeth shows him the bureau and the clock grabbed by Amelia. Amelia talks about the gold watch supposedly promised to Jimmy. He realises the truth behind the fight. He knows that Amelia wanted to get rid of him two years ago and Elizabeth didn’t want him either.

Question 5.
Compare and contrast Henry’s character with that of his wife. Support your answer with evidences from the play.
Answer:
She is greedy and wants to take some of grandfather’s things she likes before her sister arrives. She is overbearing and gets the reluctant Henry to help her shift the bureau and also put on grandfather’s slippers. She is straight talking, while Henry tells Victoria that grandfather had promised the bureau to them, she just tells Victoria to be quiet and not tell her aunt. She is rude and impolite to her sister and lacks feelings. She hurts grandfather by telling him that Elizabeth did not wish to keep him.

Henry is sensitive and does not wish to take the slippers or the bureau. He has a weaker character and allows himself to be dominated by Amelia. He is evasive and hides from the ugly truth. He tells Victoria that grandfather had promised them the bureau.

Question 6.
In the play the two daughters do not seem to be concerned at their father’s death. Do you think it is proper? If not, why?
(Encourage students to think creatively and formulate their own answers.)

Question 7.
How are the two sisters exposed in the play The Dear Departed?
Answer:
They are portrayed as greedy. Amelia is after the bureau and the clock and Elizabeth wants the gold watch. But since grandfather is alive, the truth behind the spat comes out.

Question 8.
Narrate the story of The Dear Departed from the point of view of Abel Merryweather.
Answer:
I went out to the pub and came home and fell asleep. Due to the sudden turn, I couldn’t move or speak. I saw Amelia and Henry come in my room and take the bureau but I couldn’t stop them or ask them why they were doing that. I heard voices and tried to get up but little Vicky came in, saw me and got frightened. Downstairs my daughters and sons-in-law presumed that I was dead and started grabbing my things. I am going to get married and shift out soon, as I do not want to stay with such greedy people.

Question 9.
Victoria in The Dear Departed is very upset by the behaviour of her parents. She expresses her feelings in a diary entry. As Victoria, write the diary entry.
Answer:
My grandfather is dead. The greed shown by my parents as well as by my aunt and uncle under the circumstances is appalling. Each one is more interested in benefits derived from this situation rather than grieving over their father and I am completely saddened by their attitudes.

Question 10.
In what way is the play The Dear Departed a satirical comment on the nature of human beings?
Answer:
In The Dear Departed, the playwright William Stanley Houghton highlights the degradation of moral values and the weakening relationships between the members of the family. He brings out the greed and selfishness of people for whom money is more important than relationships. The drama depicts how present generation is reacting towards the elders. They are more interested in what they will inherit and try to grab the lion’s share.

The Dear Departed Extra Questions and Answers Reference to Context

Read the extracts and answer the questions that follow.

Question 1.
“She’ll come fast enough after her share of what grandfather’s left. You know how hard she can be when she likes. Where she gets it from I can’t tell.”

(a) Who speaks these words and about whom?
(i) Mrs Slater about Victoria
(ii) Victoria about Mrs Jordan
(iii) Mrs Jordan about Mrs Slater
(iv) Mrs Slater about Mrs Jordan

(b) The speaker implies that ‘she’ is:
(i) cruel.
(ii) selfish.
(iii) generous.
(iv) loving.

(c) The literary device used in the above lines is:
(i) irony.
(ii) personification.
(iii) alliteration.
(iv) metaphor.

Question 2.
“Are we pinching it before Aunt Elizabeth comes?”

(a) What does ‘it’ refer to here?
Answer:
It refers to the bureau belonging to Abel Merry weather.

(b) How does Vicky conclude that her parents are ‘pinching it’?
Answer:
Vicky concludes her parents are pinching it because it belonged to grandfather and they are taking it without permission after his death.

(c) Mention the two realsons that Mrs Slater gives for her action.
Answer:
Mrs Slater says that she has always wanted it and if her sister Elizabeth were to see it, she would drive a hard bargain over it.

(d) What does it reveal about the difference between the attitude of the elders and that of Vicky?
Answer:
The elders are out for what they can get while Victoria has more of a sense of what is right.

Question 3.
“Be off now, and change your dress before your Aunt Elizabeth and your Uncle Ben come. It would never do for them to find you in colours.”

(a) Who says these words aind to whom?
Answer:
These words are spoken by Amelia Slater to her daughter Victoria.

(b) Why does she disapprove of the listener being in colours?
Answer:
Abel Merryweather, Amelia’s father, has died and so they should be in mourning and not wearing colours.

(c) Bring out the irony in the above statement.
Answer:
Victoria, the one in colours, is actually the only one who is mourning her grandfather’s death. Herein lies the irony.

Question 4.
“I’m wondering if they’ll come at all. When you and Elizabeth quarrelled she said she’d never set foot in your house again.”

(a) Where will ‘she’ not come?
Answer:
‘She’, that is, Elizabeth, was not expected to come to Amelia and Henry’s house.

(b) Why will she not come?
Answer:
Elizabeth was not expected to come because the two sisters had a quarrel.

(c) Why, according to the listener, will she come?
Answer:
Elizabeth would come to claim her share of what their father had left behind, in the opinion of the listener.

Question 5.
“You know how hard she can be when she likes. Where she gets it from I can’t tell.”

(a) Who says this and about whom?
Answer:
Amelia says this about her sister Elizabeth.

(b) Why does the speaker call her hard?
Answer:
Amelia says that Elizabeth will want her share of grandfather’s property and she will not compromise. She will drive a hard bargain because she is seeking to obtain money at every opportunity.

(c) Bring out the irony in the statement ‘Where she gets it from I can’t tell’?
Answer:
The irony in the statement is that even Amelia is hard and greedy like her sister Elizabeth.

Question 6.
They’ll stretch, won’t they? I’m not going to have them wasted.

(a) What is ‘they’?
Answer:
‘They’ refers to Abel Merry weather’s slippers.

(b) What does she want the listener to do? Why?
Answer:
Amelia wants Henry to wear those slippers as they are new and his own slippers are old and worn out.

(c) Why does she say ‘they’ will stretch?
Answer:
The slippers are small for Henry. Amelia says they will stretch once he starts wearing them.

Question 7.
Now, Amelia, you mustn’t give way. We’ve all got to die some time or other. It might have been worse.

(a) Who is the speaker of these lines?
Answer:
The speaker of these lines is Ben Jordan.

(b) What prompts the speaker to say these words?
Answer:
Amelia is giving way to her grief at Abel Merryweather’s death. This prompts Ben to say these words.

(c) What does he mean when he says ‘It might have been worse’?
Answer:
Ben means that it could have been one of them who had died instead of Abel Merryweather.

(d) What does it reveal about the speaker’s character?
Answer:
It shows his callousness at the death of Abel Merryweather.

Question 8.
BEN: You should have gone for another. Eh, Eliza?
MRS JORDAN: Oh, yes. It’s a fatal mistake.

(a) What does Ben mean by ‘another’?
Answer:
Ben means another doctor as Dr Pringle, Abel Merryweather’s doctor was unavailable.

(b) Why does Mrs Jordan call it a fatal mistake?
Answer:
Mrs Jordan calls it a fatal mistake because she feels a doctor may have saved Abel Merryweather’s life.

Question 9.
“He always was thoughtful in that way. He was too honourable to have ‘gone’ without paying his premium.”

(a) Where is Abel Merryweather supposed to have gone that morning?
Answer:
Abel Merryweather was supposed to pay the premium on his insurance.

(b) Why is he said to be thoughtful?
Answer:
Abel Merryweather is said to be thoughtful since he paid the premium so that the two daughters, Amelia and Elizabeth, would get the insurance money.

(c) Bring out the irony in the above statement?
Answer:
Abel Merryweather had not gone to pay the premium on his insurance but to the pub for a drink.

Question 10.
“I don’t call that delicate, stepping into a dead man’s shoes in such haste.”

(a) Who makes this comment?
Answer:
Mrs Jordan makes this comment.

(b) What prompts the speaker to say this?
Answer:
The speaker is prompted to say this when she sees Henry Slater wearing Abel Merryweather’s slippers.

(c) Bring out the significance of this statement.
Answer:
The Slaters and Jordans have started dividing Abel Merryweather’s things among themselves as soon as they presume him to be dead. Herein lies the irony as both the daughters are acting in the same greedy manner.

Question 11.
“And you, too. Are you such a poor creature that you must do every dirty thing she tells you?”

(a) Who is the ‘poor creature’?
Answer:
Henry Slater is the ‘poor creature’.

(b) Why is he being called a ‘poor creature’?
Answer:
Henry is called a ‘poor creature’ since he does not stand up to his wife and does everythinglthat she tells him to do.

(c) What dirty deed had he done at her bidding?
Answer:
At her bidding, Henry had shifted his father-in-law’s bureau and clock to their room in order to keep it to themselves.

RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G

Online Education for RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G

These Solutions are part of Online Education RS Aggarwal Solutions Class 9. Here we have given RS Aggarwal Solutions Class 9 Chapter 2 Polynomials Ex 2G.

Other Exercises

Factorize :

Question 1.
Solution:
x2 + 11x + 30
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 1

Question 2.
Solution:
x2 + 18x + 32
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 2.1

Question 3.
Solution:
x2 + 7x – 18
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 3.1

Question 4.
Solution:
x2 + 5x – 6
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 4.1

Question 5.
Solution:
y2 – 4y + 3
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 5.1

Question 6.
Solution:
x2 – 21x + 108
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 6.1

Question 7.
Solution:
x2 – 11x – 80
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 7.1

Question 8.
Solution:
x2 – x – 156
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 8.1

Question 9.
Solution:
z2 – 32z – 105
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 9.1

Question 10.
Solution:
40 + 3x – x2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 10.1

Question 11.
Solution:
6 – x – x2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 11.1

Question 12.
Solution:
7x2 + 49x + 84
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 12.1

Question 13.
Solution:
m2 + 17mn – 84n2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 13.1

Question 14.
Solution:
5x2 + 16x + 3
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 14.1

Question 15.
Solution:
6x2 + 17x + 12
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 15.1

Question 16.
Solution:
9x2 + 18x + 8
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 16.1

Question 17.
Solution:
14x2 + 9x + 1
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 17.1

Question 18.
Solution:
2x2 + 3x – 90
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 18.1

Question 19.
Solution:
2x2 + 11x – 21
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 19.1

Question 20.
Solution:
3x2 – 14x + 8
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 20.1

Question 21.
Solution:
18x2 + 3x- 10
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 21.1

Question 22.
Solution:
15x2 + 2x – 8
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 22.1

Question 23.
Solution:
6x2 + 11x – 10
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 23.1

Question 24.
Solution:
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 24.1

Question 25.
Solution:
24x2 – 41x + 12
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 25.1

Question 26.
Solution:
2x2 – 7x – 15
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 26.1

Question 27.
Solution:
6x2 – 5x – 21
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 27.1

Question 28.
Solution:
10x2 – 9x – 7
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 28.1

Question 29.
Solution:
5x2 – 16x – 21
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 29.1

Question 30.
Solution:
2x2 – x – 21
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 30.1

Question 31.
Solution:
15x2 – x – 28
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 31.1

Question 32.
Solution:
8a2 – 27ab + 9b2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 32.1

Question 33.
Solution:
5x2 + 33xy -14y2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 33.1

Question 34.
Solution:
3x3 – x2 – 10x
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 34.1

Question 35.
Solution:
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 35.1

Question 36.
Solution:
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 36.1

Question 37.
Solution:
√2x2 + 3x + √2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 37.1

Question 38.
Solution:
√5x2 + 2x – 3√5
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 38.1

Question 39.
Solution:
2a2 + 3√3x + 3
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 39.1

Question 40.
Solution:
2√3x² + x – 5√3
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 40.1

Question 41.
Solution:
5√5x2 + 20x + 3√5
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 41.1

Question 42.
Solution:
7√x² – 10x – 4√2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 42.1

Question 43.
Solution:
6√3 x2 – 47x + 5√3
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 43.1

Question 44.
Solution:
7x2 + 2√14x + 2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 44.1

Question 45.
Solution:
2(x + y)2 – 9(x + y) – 5
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 45.1

Question 46.
Solution:
9(2a-b)2-4(2a-b)-13
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 46.1

Question 47.
Solution:
7(x – 2y)2 – 25 (x – 2y) + 12
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 47.1

Question 48.
Solution:
4x4 + 7x2-2
RS Aggarwal Class 9 Solutions Chapter 2 Polynomials Ex 2G 48.1

Hope given RS Aggarwal Solutions Class 9 Chapter 2 Polynomials Ex 2G are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

Online Education HOTS Questions for Class 9 Science Chapter 10 Gravitation

Online Education HOTS Questions for Class 9 Science Chapter 10 Gravitation

These Solutions are part of HOTS Questions for Class 9 Science. Here we have given HOTS Questions for Class 9 Science Chapter 10 Gravitation

Question 1.
Gravitational force between two masses m1 and m2 separated by a distance r in air is F. What is the gravitational force between these masses separated by the same distance r in vacuum ?
Answer:
Gravitational force between two masses does not depend on the medium in which they are placed. Therefore, gravitational force between the masses in vacuum will also be F.

More Resources

Question 2.
Can a body has mass, but no weight ? Give reason for your answer. (CBSE 2015)
Answer:
Mass of a body is the quantity of matter contained in the body. However, weight of body = mg. Weight of a body is zero, when value of g = 0. The value of ‘g at the centre of the earth is zero, therefore, weight of the body at the centre of the earth is zero. Thus, body can have mass but no weight at the centre of the earth.

Question 3.
The value of acceleration due to gravity on a planet ‘A’ is ‘g’ What will be the value of acceleration due to gravity on another planet B whose mass is same as that of the planet ‘A’ but its radius is double the radius of planet ‘A’ ?
Answer:
HOTS Questions for Class 9 Science Chapter 10 Gravitation image - 1

Hope given HOTS Questions for Class 9 Science Chapter 10 Gravitation are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

The Lost Child Extra Questions and Answers Class 9 English Moments

The Lost Child Extra Questions and Answers Class 9 English Moments

Here we are providing Online Education for The Lost Child Extra Questions and Answers Class 9 English Moments, Extra Questions for Class 9 English was designed by subject expert teachers. https://ncertmcq.com/extra-questions-for-class-9-english/

Online Education for The Lost Child Extra Questions and Answers Class 9 English Moments

The Lost Child Extra Questions and Answers Short Answer Type

The Lost Child Class 9 Extra Questions And Answers Question 1.
What are the things the child sees on his way to the fair?
Answer:
He sees people gaily dressed, some on horses, some in bamboo or bullock carts. He also sees toys, dragon ‘flies, insects, worms, flowers, and doves on his way to the fair.

The Lost Child Extra Question Answer Question 2.
Why does the child lag behind?
Answer:
He lags behind because he is attracted by several of the things he sees on the way like toys, sweetmeats, dragonflies, flower garlands, the snake charmer and the roundabout.

The Lost Child Extra Question Answers Pdf Question 3.
What are the things that he wants at the fair?
Answer:
At first he wanted a burfi, then a garland of gulmohur flowers, next some colourful balloons, after that he was attracted by the snake charmer and finally he wanted a ride on the roundabout.

Extra Questions Of The Lost Child Question 4.
Why does the child move on without waiting for his parents’ answer whenever he asked for things that attracted him?
Answer:
He moves on without waiting for an answer because he knew they would not pay attention to his demands or give him what he asked for.

Ncert Solutions For Class 9 English Moments Chapter 1 Extra Questions Question 5.
When does the child realize that he had lost his way?
Answer:
At the roundabout, when he turned to request his parents to allow him to sit on the ride, he did not get any reply. When he looked around for them he realized he had strayed away from his parents and lost his way.

The Lost Child Class 9 Extra Questions Question 6.
How has the lost child’s anxiety and insecurity been described?
Answer:
His anxiety and insecurity have been described through his reaction to his realisation that he was lost. Tears rolled down his cheeks, his throat became dry, his face flushed and convulsed with fear and he ran in all directions in panic without knowing where to go.

Extra Questions For Class 9 English Moments Chapter 1 Question 7.
Why does the lost child lose interest in the things that he had wanted earlier?
Answer:
He lost all interest in the things that he had wanted earlier because he felt fearful and insecure at being separated from his parents and all he wanted was to be reunited with them.

The Lost Child Short Question Answer Question 8.
What do you think happens in the end? Does the child find his parents?
Answer:
This question can be answered in either way. In my opinion the child is reunited with his parents who are also searching for him and find him crying in a stranger’s lap.
OR
No, the child is not reunited with his parents but is taken by the man who finds him and is brought up by him.

The Lost Child Class 9 Questions And Answers Question 9.
Why was the fair being held in the village?
Answer:
It was being held to celebrate the spring season.

Class 9 The Lost Child Extra Questions Question 10.
What tells us that the little boy was excited about going to the fair?
Answer:
The fact that the little boy has been described as “brimming over with life and laughter” tells us that he was happy and excited to be going to the fair.

Class 9 English The Lost Child Extra Questions Question 11.
Compare the reactions of the father and mother at the child’s request for a toy.
Answer:
The father glared at him angrily ‘in his familiar tyrant’s way’ while the mother looked at him tenderly and diverted his attention from the toys.

Extra Questions From The Lost Child Question 12.
What made the mother caution the child?
Answer:
The fact that the child had wandered off into the mustard field trying to catch a butterfly made the mother call out to him to come back on to the footpath.

The Lost Child Long Question Answer Question 13.
What was the boy engrossed in when his parents sat in the shade of a grove, near a well?
Answer:
The boy was engrossed in watching little insects and worms that were teeming out along the footpath.

Lost Child Class 9 Extra Questions Question 14.
What diverted the child’s attention from the shower of flower petals in the grove?
Answer:
The cooing of doves diverted the child’s attention from the raining flower petals.

Class 9 English Moments Chapter 1 Extra Questions Question 15.
How did the boy react on nearing the village where the fair was being held? Why?
Answer:
He felt both attracted and repelled at the sight of the large number of people who had converged at the village to enjoy the fair.

The Lost Child Important Questions Question 16.
Why did the child not ask his parents to buy him the burfi?
Answer:
The child knew that his parents would not listen to his request and would call him greedy for wanting

The Lost Child Class 9 Important Questions Question 17.
Why did the child move away from the flower seller without asking his parents for a garland?
Answer:
He was aware that his parents would refuse to buy him a garland and say that they were cheap.

Question 18.
Why did the child not ask his parents to buy him balloons even though he was fascinated by them?
Answer:
He knew his parents would say that he was too old to play with the balloons so he did not ask his parents to buy them for him.

Question 19.
What made the child move on from the snake charmer?
Answer:
The child had been forbidden by his parents from listening to the music being played by the-snake charmer,which they had termed as coarse, so he moved away from the snake-charmer.

Question 20.
Where did the child finally decide to ask his parents to let him enjoy the delights at the fair? Why?
Answer:
At the roundabout the sight of the machine in full swing with men and women shrieking, crying and laughing out aloud in excitement, encouraged the child to ask his parents to be permitted to ride the roundabout.

Question 21.
Where and how did the child meet his saviour?
Answer:
The child met his saviour near the entrance of a temple where he was almost at the point of being trampled under the feet of the jostling crowd.

Question 22.
How did the man try to quieten the crying lost child?
Answer:
He first took him to the roundabout, then to the snake-charmer, next the balloon seller, after that to the flower-seller and finally to the sweetmeat seller, hoping to quieten the crying lost child.

Question 23.
How was the boy’s reaction to the attractions of the fair different after getting separated from his parents?
Answer:
He lost all interest in the attractions of the fair and kept crying for his parents.

Question 24.
Do you think the title of the story is appropriate?
Answer:
Yes, the title appropriately captures the essence of the story. It highlights the plight of a little child who is lost in a fair and it captures the emotions that the child goes through on being separated from his parents. It shows how the child who a moment ago is excited at the sights and sounds of the fair suddenly loses interest in all these sights once he realises that he is lost.

The Lost Child Extra Questions and Answers Long Answer Type

Question 1.
Describe in detail all the attractions that the child is drawn to till he gets lost in the fair.
Answer:
Right till the time he loses his parents, the child is attracted to it. several things that he sees on his way. At first it is the toys being sold at the wayside shops. Then he is attracted to the dragonflies in the mustard field. Next he is drawn to the worms and insects on the footpath and the shower of flower petals and the cooing of the pigeons. On reaching the fair he is first tempted by the goodies being sold by the sweetmeat seller and then by the colourful balloons of the balloon-seller. Next he is drawn by the sound of the snake charmer and finally he is mesmerized by the roundabout with children and adults enjoying the rides.

Question 2.
Do you consider the child’s behaviour as depicted in the story normal? Give reasons for your answer.
Answer:
Yes, the child’s behaviour was normal. The story very clearly depicts the behaviour of a young child who is attracted by everything he sees around him. The child is not only attracted to toys and sweets but also fascinated by the natural wonders of the world like dragonflies, pigeons, flowers and snakes.

This is a reflection of the universal phenomenon of a child’s attraction and fascination with the natural world. As mentioned in the story the child is both ‘repelled and fascinated’ by the colourful world around him which is normal for any young child. The crowds and noise repel a child while the colourful world and the sights of the fair fascinate him.

Question 3.
The story describes certain attractions which may not be so attractive to a modern child. Can you pick up some of them from the story – ‘The Lost Child’.
Answer:
A modem city child has very little interaction with nature on a daily basis, unlike the lost child. They have very little possibility of being allowed to run wild in a yellow mustard field or being interested in doing so. Technology has taken away a lot of their time and hence he or she does not have the time to run after dragonflies or butterflies or simply rejoice under the rain of flower petals from a gulmohur tree.

With their exposure to amusement parks and water parks with mechanised rides and an artificially created ambience, they would probably not even feel comfortable in natural surroundings. However if the child is allowed free rein to interact with nature he/she would probably find the natural affinity that a human being has for nature and behave in the same manner as the lost child in the story.

Question 4.
Describe the character of the child as depicted in the story.
Answer:
The child is very young, innocent and full of joy and energy. He finds everything around him exciting and fascinating, whether a dragonfly or toy displayed in a toy shop. Like any child he is easily distracted and his desires and interests keep on changing from sweetmeats to balloons to rides. He is not used to large crowds and is ‘repelled and fascinated’ by them.

His whole world revolves around his parents and he is deeply affected at his separation from them. He is obedient and disciplined and does not throw a tantrum to get his object of desire. He fears his father and approaches his mother whenever he is tempted by any of the objects he sees during his journey to the fair and at the fair itself.

Question 5.
How does the child in the story lose himself? How far is he responsible for his predicament?
Answer:
The child is wholly responsible for his predicament because at every stage we find him wandering off after one attraction or the other inspite of repeated instructions from his mother not to do so. Initially we find him staring down in front of the wayside toy shops. Next he wanders off into the mustard fields, chasing dragonflies. Then he slows down to admire the insects and worms that line the footpath.

After that he gets distracted by the rain of flower petals and the cooing of the doves and has to be pulled back to the main road by his mother. On entering the fair he again slows down in front of the sweetmeat seller, the flower seller, the snake charmer and the roundabout before realising that he is completely on his own.

 

Online Education for RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B

Online Education for RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B

These Solutions are part of RS Aggarwal Solutions Class 9. Here we have given RS Aggarwal Solutions Class 9 Chapter 11 Circle Ex 11B.

Other Exercises

Question 1.
Solution:
(i) O is the centre of the circle
∠OAB = 40°, ∠OCB = 30°
Join OB.
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q1.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q1.2
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q1.3

Question 2.
Solution:
O is the centre of the cirlce and ∠AOB = 70°
∵ Arc AB subtends ∠AOB at the centre and ∠ACB at the remaining part of the circle.
∵ ∠ACB = \(\frac { 1 }{ 2 } \) ∠AOB = \(\frac { 1 }{ 2 } \) x 70°
=> ∠ACB = 35°
or ∠OCA = 35°
In ∆OAC,
OA = OC (radii of the same circle)
∴ ∠OAC = ∠OCA = 35° Ans.

Question 3.
Solution:
In the figure, O is the centre of the circle. ∠PBC = 25°, ∠APB =110°
∠ APB + ∠ BPC = 180° (Linear pair)
=> 110° + ∠ BPC = 180°
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q3.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q3.2

Question 4.
Solution:
O is the centre of the circle
∠ABD = 35° and ∠B AC = 70°
BOD is the diameter of the circle
∠BAD = 90° (Angle in a semi circle)
But ∠ADB + ∠ABD + ∠BAD = 180° (Angles of a triangle)
=> ∠ADB + 35° + 90° = 180°
=> ∠ADB + 125° = 180°
=> ∠ADB = 180° – 125° = 55°
But ∠ACB = ∠ADB (Angles in the same segment of the circle)
∠ACB = 55° Ans.

Question 5.
Solution:
O is the centre of a circle and ∠ACB = 50°
∴ arc AB subtends ∠ AOB at the centre and ∠ ACB at the remaining part of the circle.
∴ ∠ AOB = 2 ∠ ACB
= 2 x 50° = 100
∴ OA = OB (radii of the same circle)
∴ ∠ OAB = ∠ OBA (Angles opposite to equal sides)
Now in ∆ OAB,
∠ OAB + ∠ OBA + ∠ AOB = 180°
=> ∠ OAB + ∠ OAB + ∠ AOB = 180° (∠OAB = ∠OBA)
=> 2 ∠ OAB + 100°= 180°
=> 2 ∠ OAB = 180° – 100° = 80°
=> ∠OAB = \(\frac { { 80 }^{ o } }{ 2 } \) = 40°
Hence, OAB = 40° Ans.

Question 6.
Solution:
(i) In the figure,
∠ABD = 54° and ∠BCD = 43°
∠BAD = ∠BCD (Angles in the same segment of a circle)
∠BAD = 43°
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q6.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q6.2

Question 7.
Solution:
Chord DE || diameter AC of the circle with centre O.
∠CBD = 60°
∠CBD = ∠ CAD
(Angles in the same segment of a circle)
∠CAD = 60°
Now in ∆ ADC,
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q7.1

Question 8.
Solution:
In the figure,
chord CD || diameter AB of the circle with centre O.
∠ ABC = 25°
Join CD and DO.
AB || CD
∠ ABC = ∠ BCD (alternate angles)
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q8.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q8.2

Question 9.
Solution:
AB and CD are two straight lines passing through O, the centre of the circle and ∠AOC = 80°, ∠CDE = 40°
∠ CED = 90° (Angle in a semi circle)
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q9.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q9.2

Question 10.
Solution:
O is the centre of the circle and ∠AOB = 40°, ∠BDC = 100°
Arc AB subtends ∠AOB at the centre and ∠ ACB at the remaining part of the circle
∠ AOB = 2 ∠ ACB
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q10.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q10.2

Question 11.
Solution:
Chords AC and BD of a circle with centre O, intersect each other at E at right angles.
∠ OAB = 25°. Join OB.
In ∆ OAB,
OA = OB (radii of the same circle)
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q11.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q11.2

Question 12.
Solution:
In the figure, O is the centre of a circle ∠ OAB = 20° and ∠ OCB = 55° .
In ∆ OAB,
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q12.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q12.2

Question 13.
Solution:
Given : A ∆ ABC is inscribed in a circle with centre O and ∠ BAC = 30°
To Prove : BC = radius of the circle
Const. Join OB and OC
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q13.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q13.2

Question 14.
Solution:
In a circle with centre O and PQ is its diameter. ∠PQR = 65°, ∠SPR = 40° and ∠PQM = 50°
(i) ∠PRQ = 90° (Angle in a semicircle) and ∠PQR + ∠RPQ + ∠PQR = 180° (Angles of a triangle)
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q14.1
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q14.2
RS Aggarwal Class 9 Solutions Chapter 11 Circle Ex 11B Q14.3

Hope given RS Aggarwal Solutions Class 9 Chapter 11 Circle Ex 11B are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

Sound Class 9 Extra Questions and Answers Science Chapter 12

Online Education for Sound Class 9 Extra Questions and Answers Science Chapter 12

In this page, we are providing Online Education for Sound Class 9 Extra Questions and Answers Science Chapter 12 pdf download. NCERT Extra Questions for Class 9 Science Chapter 12 Sound with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Online Education for Class 9 Science Chapter 12 Extra Questions and Answers Sound

Extra Questions for Class 9 Science Chapter 12 Sound with Answers Solutions

Sound Class 9 Extra Questions Very Short Answer Type

Class 9 Science Chapter 12 Extra Questions And Answers Question 1.
What are longitudinal waves?
Answer:
A wave in which the particles of the medium vibrate back and forth in the ‘same direction’ in which the wave is moving, is called as a longitudinal wave.

Class 9 Science Chapter Sound Extra Question Answer Question 2.
What are transverse waves?
Answer:
A wave in which the particles of the medium, vibrate up and down ‘at right angle’ to the direction in which the wave is moving, is called a transverse wave.

Sound Class 9 Extra Questions Answers Question 3.
Define wavelength. What is its symbol and its SI unit?
Answer:
The distance between two consecutive compressions (C) or two consecutive rarefactions (R) is called the wavelength. The wavelength is denoted by (Greek letter ‘lambda’). Its SI unit is the metre (m).

Sound Class 9 Extra Questions Question 4.
Define frequency. What is its symbol and its SI unit?
Answer:
The number of complete waves (or cycles) produced per second is called a frequency of sound waves. It is denoted by f. The SI unit of frequency is hertz (Hz).

Sound Class 9 Worksheet With Answers Question 5.
What is one hertz?
Answer:
A vibrating body producing 1 wave per second is said to have a frequency of 1 Hz.

Sound Extra Questions And Answers Class 9 Question 6.
Define amplitude. What is its symbol and its SI unit?
Answer:
The magnitude of the maximum disturbance in the medium on either side of the mean value is called the amplitude of wave. It is denoted by A. The SI unit is the metre (m).

Sound Chapter Class 9 Extra Questions Question 7.
What is ‘audible’ sound?
Answer:
The sound which we are able to hear is called ‘audible’ sound. The audible range of sound for human beings extends from about 20 Hz to 20000 Hz.

Extra Questions On Sound Class 9 Question 8.
What do you mean by an echo?
Answer:
The repetition of sound caused by the reflection of sound waves is called an ‘echo’.

Numericals On Sound For Class 9 Question 9.
What do you understand by the terms “compression” and rarefaction?
Answer:
A region of high pressure of a medium when a sound wave travels through it is called compression.
A region of low pressure of a medium when a sound wave travels through it is called rarefaction.

Class 9 Science Sound Extra Questions Question 10.
What do you understand by the pitch of a sound?
Answer:
Pitch of a sound is the characteristic of sound that depends on the frequency received by a human ear.

Extra Questions Of Sound Class 9 Question 11.
What do you understand by the loudness of sound?
Answer:
The amplitude of the vibrating body determines the loudness of the sound. Larger the amplitude of vibration, larger the loudness of the sound produced.

Sound Chapter In Physics Class 9 Questions And Answers Question 12.
Define the characteristic “timbre” or “quality” of a sound.
Answer:
Quality or timbre is a characteristic of a sound which enables us to distinguish between two sounds of the same loudness and pitch.

Sound Class 9 Important Questions With Answers Question 13.
What is Sonar?
Answer:
Sonar is a device that uses ultrasonic wave to measure the distance, direction and speed of the underwater object.

Class 9 Sound Extra Questions Question 14.
What is Echocardiography?
Answer:
The technique of obtaining images of the heart by using the reflection of ultrasonic waves from various parts of the heart is called echocardiography.

Class 9 Science Chapter Sound Extra Question & Answer Question 15.
What is ultrasonography?
Answer:
The technique of obtaining images of internal organs of the body by using echoes of ultrasonic waves is called ultrasonography.

Question 16.
What is a stethoscope?
Answer:
The stethoscope is a medical instrument used for listening sounds produced within the body, chiefly in the heart or lungs.

Question 17.
What are infrasonic waves?
Answer:
The waves of frequency less than 20 Hz are called infrasonic waves.

Question 18.
What is ultrasound?
Answer:
The waves of frequency greater than 20,000 Hz are called ultrasonic waves or ultrasound.

Question 19.
Speed of sound is more on a hotter day. Explain why.
Answer:
Speed of sound increases with increase in temperature.

Question 20.
WrIte down the SI unit of (i) frequency (ii) wavelength.
Answer:
SI unit of wavelength is m and frequency is Hz.

Sound Class 9 Extra Questions Numericals

Question 1.
The sound produced by a thunderstorm is heard 10 s after the lightning is seen. Calculate the approximate distance of the thunder cloud. (Given the speed of sound = 340 ms’).
Ans. Given, t = 10 s
υ = 340 m/s
distance, x = υ x t = 340 x 10 = 3400 m.

Question 2.
What is the frequency of wave with time period 0.025 s?
Answer:
Given, t = 0.025 s
frequency, v = \(\frac{1}{t}=\frac{1}{0.025}\) = 40 Hz.

Sound Class 9 Extra Questions Short Answer Type 1

Question 1.
What is sound? When is the sound produced? Give examples.
Answer:
The sensation felt by our ears is called sound. A sound is a form of energy which makes us hear. When an object is set into vibrations, the sound is produced. For example, the vibrating diaphragm of a drum produces sound, the vibrating string of a guitar produces sound, the vibrating diaphragm of speakers of a radio produce sound, the vibrating end of a drilling machine produces sound, etc.

Question 2.
State the conditions to hear an echo.
Answer:
The conditions to hear an echo are:

1. Echo can be heard only if it is produced at least \(\frac {1}{10}\) th of a second (0.1 s) after the original sound.

2. The speed of sound in air is 344 m/s. Let us calculate the minimum distance from the reflecting surface, which is necessary to hear an echo.
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 1
∴ Distance travelled = 344 x \(\frac {1}{10}\) = 34.4 metres
Thus, the distance travelled by the sound in \(\frac {1}{10}\) th of a second is 34.4 m. This means that the minimum distance between the source of the sound and the listeners should be 17.2 metres.

3. Echo can be heard only if the reflecting surface is large.

Question 3.
Bats search out prey and fly in the dark night by emitting ultrasound. Explain.
Answer:
Bats search out prey and fly in the dark night by emitting and detecting reflections of ultrasonic waves. The high-pitched ultrasonic squeaks of the bat are reflected from the obstacles or prey and returned to bat’s ear. The nature of reflections tells the bat where the obstacle or prey is and what it is like.

Question 4.
Mention one advantage and one disadvantage of reverberation.
Answer:
A certain amount of reverberation improves the quality of sound of orchestral and choral music. However excessive reverberation makes the speech or music indistinct.

Question 5.
How does a megaphone works?
Answer:
A megaphone works on the principle of reflection of sound. In this instrument, a tube followed by a conical opening reflects sound successively to guide most of the sound from the source in the forward direction towards the audience.

Sound Class 9 Extra Questions Numericals

Question 1.
If the velocity of sound in air is 340 ms-1. Calculate
1. wavelength when the frequency is 256 Hz.
2. frequency when the wavelength is 0.85 m.
Answer:
Given,
velocity of sound, υ = 340 m/s
1. v = 256 Hz
using, υ = λ v
λ = \(\frac {υ}{λ}\) = \(\frac {340}{256}\) = 1.33m

2. λ = 0.85
using, u = λv
λ = \(\frac {υ}{λ}\) = \(\frac {340}{0.85}\) = 400Hz

Question 2.
30 waves pass through a point in 3 seconds. If the distance between two crests is 2 m. Calculate
(a) frequency
(b) wavelength.
Answer:
30 waves in 3 seconds
υ = \(\frac {30}{3}\) = 10Hz
∴ λ = 2m.

Sound Class 9 Extra Questions Short Answer Type 2

Question 1.
What is the reflection of sound? State the laws of reflection.
Answer:
The bouncing back of sound from a hard surface is called a reflection of sound. The laws of reflection are:
1. The incident sound wave, the reflected sound wave and the normal at the point of incidence, all lie in the same plane.
2. The angle of incidence of sound is always equal to the angle of reflection of sound.

Question 2.
On what factor does the speed of sound depend?
Answer:
The speed of sound depends upon the following:

  • The nature of the material (or medium) through which it travels. In general, sound travels fastest in solids, slower in liquids and slowest in gases.
  • The humidity of the air. As the humidity of air increases, sound travels faster. Sound has more speed in humid air than in dry air.
  • The temperature. The speed of sound in air at 0°C is 332 m/s whereas at 20°C, it is 344 m/s. Thus, as the temperature rises, the speed of sound also increases.

Question 3.
Write a note on ‘ultrasonic sounds’.
Answer:

  • The sounds of frequencies higher than 20,000 Hz are known as ‘ultrasonic sounds’ (or just‘ultrasounds’).
  • Human beings cannot hear ultrasonic sounds. Children under the age of five and some animals, such as dogs can hear sounds up to 25,000 Hz.
  • As people grow older, their hearing sensation for higher frequencies becomes weaker.
  • Ultrasonic sounds are used by dolphins, bats and porpoises to navigate in dark and to catch their prey.
  • Some moths can hear high-frequency ultrasonic squeaks of the bat and know when a bat is flying nearby and are able to escape capture. Rats also play games by producing ultrasound.

Question 4.
Write three differences between transverse and longitudinal waves.
Answer:
Transverse waves:

  • In the transverse waves, the particles of the medium vibrate perpendicular to the direction of wave motion.
  • These waves travel in the form of alternate crest and trough.
  • These waves can be transmitted through solid or liquid surfaces.

Longitudinal waves:

  • In longitudinal waves, the particles of the medium vibrate along the direction of wave motion.
  • These waves travel in the form of alternate compression and rarefactions.
  • These waves can be transmitted through all the three types of media viz., solid, liquid and gases.

Question 5.
Write down three differences between a sound wave and lightwave.
Answer:
Sound wave:

  • It travels in the form of longitudinal waves.
  • It requires a medium for its propagation.
  • It travels through air with a speed of 332 propagation. m/s at 0°C.

Lightwave:

  • It travels in the form of a transverse wave.
  • It does not require a medium for its propagation.
  •  It travels through air with a speed of nearly 3 x 108 m/s.

Sound Class 9 Extra Questions Long Answer Type

Question 1.
State three applications of reflection of sound.
Answer:
1. Megaphone and a bulb horn: Megaphones or loudhailers, horns, musical instruments such as trumpets and she Hana is, are all designed to send sound in a particular direction without spreading it in all directions, as shown in the figure. In these instruments, a tube followed by a conical opening reflects sound successively to guide most of the sound waves from the source in the forward direction towards the audience.
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 2

2. Stethoscope: Stethoscope is a medical instrument used for listening to sounds produced within the body, chiefly in the heart or lungs. In stethoscopes, the sound of the patient’s heartbeat reaches the doctor’s ears by multiple reflections of sound, as shown in the figure.
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 3
3. Soundboard: Generally the ceiling of concert halls, conference halls and cinema halls are curved so that sound after reflection reaches all corners of the hall, as shown in the figure. Sometimes a curved soundboard may be placed behind the stage so that the sound, after reflecting from the soundboard, spreads evenly across the width of the hail (Fig).
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 4

Question 2.
State the applications of ultrasound.
Answer:
Ultrasounds are high-frequency waves. Ultrasounds are able to travel along well-defined paths even in the presence of obstacles. Ultrasounds are used extensively in industries and for medical purposes.

1. Ultrasound is generally used to clean parts located in hard-to-reach places, for example, spiral tube, odd-shaped parts, electronic components, etc. Objects to be cleaned are placed in a cleaning solution and ultrasonic waves are sent into the solution. Due to high frequency, the particles of dust, grease and dirt get detached and drop out. The objects thus get thoroughly cleaned.

2. Ultrasounds can be used to detect cracks and flaws in metal blocks. Metallic components are generally used in the construction of big structures like buildings, bridges, machines and also scientific equipment. The cracks or holes inside the metal blocks, which are invisible from outside reduces the strength of the structure.

Ultrasonic waves are allowed to pass through the metal block and detectors are used to detect the transmitted waves. If there is even a small defect, the ultrasound gets reflected back indicating the presence of the flaw or defect.

3. Ultrasonic waves are made to reflect from various parts of the heart and form the image of the heart. This technique is called ‘echocardiography’.

4. An ultrasound scanner is an instrument which uses ultrasonic waves from getting images of internal organs of the human body. A doctor may image the patient’s organs such as liver, gall bladder, uterus, kidney, etc. It helps the doctor to detect abnormalities, such as stones in the gall bladder and kidney or tumours in different organs.

In this technique, the ultrasonic waves travel through the tissues of the body and get reflected from a region where there is a change of tissue density. These waves are then converted into electrical signals that are used to generate images of the
organ.

These images are then displayed on a monitor or printed on a film. This technique is called ‘ultrasonography’. Ulträsonography is also used for examination of the foetus during pregnancy to detect congenital defects and growth abnormalities.

5. Ultrasound may be employed to break small ‘stones’ formed in the kidneys into fine grains. These grains later get flushed out with urine.

Sound Class 9 Extra Questions HOTS

Question 1.
Why do we hear the sound produced by the humming bees while the sound of vibrations of a pendulum is not heard?
Answer:
This is because the frequency of the sound produced by humming bees lies in audible range and frequency of the sound of vibrations of pendulum lies in the infrasonic region.

Question 2.
Sounds of same loudness and pitch but produced by different musical instruments like a violin and flute are distinguishable.
Answer:
It is the quality of sound which enables us to distinguish between two sounds of the same loudness and pitch.

Question 3.
Which of the two graphs (a) and (b) shown in the figure below represents the human voice is likely to be the male voice? Give a reason for your answer. (NCERT Exemplar)
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 5
Answer:
Graph a represents the male voice because the frequency of male voice is less than that of the female voice.

Question 4.
The given graph (Fig.) shows the displacement versus time relation for a disturbance travelling with velocity 1500 ms-1. Calculate the wavelength of the disturbance. (NCERT Exemplar)
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 6
Answer:
Here, frequency, u = \(\frac {1}{T}\)
T = 2 ms = 2 x 10-6 s
Hence υ = \(\frac{1}{2 \times 10^{-6}}\) = 5 x 105 Hz
using relation, λ. = \(\frac{v}{v}=\frac{1500}{5 \times 10^{5}}\) = 3 x 10-2 m

Question 5.
For hearing the loudest ticking sound heard by the ear, find the angle x in the Figure. (NCERT Exemplar)
Sound Class 9 Extra Questions and Answers Science Chapter 12 img 7
Answer:
Here angle of incidence,
i = 90° – 50° = 40°
Angle of incidence (i) or Angle of reflection (x)
x = i = 40°.

Sound Class 9 Extra Questions Value Based (VBQs)

Question 1.
Sumeet went to a hill station with his parents and elder sister Kirti. He was experiencing the scenic beauty of a hill station for the first time. One day they were walking in a forest area, Sumeet loudly called out ‘Kirti Didi’. He was surprised that he could distinctly hear the same sound twice. He discussed this with his sister and she explained the reason behind this echo.
Answer:
(a) The repetition of sound caused by the reflection of sound waves is called an echo.
(b) Kirti is intelligent and helpful.

Question 2.
Tinku studies in class 9th. Once he was suffering from cold and cough and was running a high temperature. His mother took him to a doctor. The doctor examined the chest and back of Tinku with the help of a device ‘stethoscope’. While examining with stethoscope doctor asked Tinku to take longer breaths. After examining Tinku, the doctor prescribed some drugs.

By regular use of these drugs, Tinku was normal within four days. But he could not understand the purpose of being examined by the use of a stethoscope. During winter break his cousin Honey, who was studying in a medical college, visited their place. On the request of Tinku, Honey explained the purpose of the stethoscope and its action.
(a) What is a stethoscope?
(b) What quality was shown by Honey?
Answer:
(a) The stethoscope is a medical instrument used for listening to sounds produced within the body, chiefly in the heart or lungs.
(b) Honey is intelligent and helpful.

Question 3.
On a hot summer afternoon, a man was shouting through a megaphone. He was ‘zip-repairer’. As Arshi was preparing for her examination, she got disturbed. She inquired her father about the instrument being used by the ‘zip-repairer’. The father told her that it was a megaphone also known as ‘loud hailer’.
(a) State the principle on which the megaphone works.
(b) Why did Arshi get disturbed?
Answer:
(a) Megaphone works on the principle of multiple reflections.
(b) Arshi got disturbed by noise pollution.

Question 4.
Reena’s grandmother took her mother to a doctor as she was four months pregnant for ultrasonography. But she showed her interest in determining whether the child is a boy or a girl. The doctor was annoyed and refused to disclose the gender of the child.
(a) What is ultrasonography?
(b) Write down the values shown by the doctor.
Answer:
(a) The technique of obtaining images of internal organs of the body by using echoes of ultrasound waves is called ultrasonography.
(b) A Doctor is a law-abiding person.

Online Education HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules

Online Education HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules

These Solutions are part of Online Education HOTS Questions for Class 9 Science. Here we have given HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules

Question 1.
(a) An element shows variable valencies 4 and 6. Write the formulae of its two oxides.
(b) An element forms an oxide A2O5.
(i) What is the valency of the element A ?
(ii) What will be the formula of the chloride of the element ?
Answer:
(a) Let the element be represented by the symbol E.
Formula of oxide in which valency of E is 4 = E2O4 or EO2
Formula of oxide in which valency of E is 6 = E2O6 or EO3
(b) Formula of oxide of the element = A2O5
(i) The valency of the element A in the oxide = 5+
(ii) The formula of the chloride of the element A = ACl5.

More Resources

Question 2.
On analysing an impure sample of sodium chloride, the percentage of chlorine was found to be 45.5 What is the percentage of pure sodium chloride in the sample ?
Answer:
HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules 1

Question 3.
(a) Why does not the atomic mass of an element represent the actual mass of its atom ?
(b) The atomic mass of an element is in fraction. What does it mean ?
(c) Why is the value of Avogadro’s number 6.022 x 1023 and not any other value ?
(d) Does one gram mole of a gas occupy 24.4 L under all conditions of temperature and pressure ?
Answer:
(a) Atoms of different elements are very small in size and their actual mass are extremely small. For example, the mass of an atom of hydrogen is 1.67 x 10-27 kg. To solve this problem, we consider the relative atomic masses of the elements. The relative atomic mas of hydrogen is 1 u and its corresponding gram atomic mass is 1 g.
(b) If the atomic mass of an element is in fraction, this means that it exists in the form of isotopes. The atomic mass is the average atomic mass and is generally fractional.
(c) It represents the number of atoms in one gram atom of an element or the number of molecules in one gram mole of a compound. If we divide the atomic mass of an element by actual mass of its atom, the value is 6.022 x 1023. Similarly, by dividing the molecular mass of a compound by the actual mass of its molecule, the same result is obtained.
(d) No, one gram mole of a gas occupies a volume of 22.4 L only under N.T.P. conditions i.e. at 273 K temperature and under 760 mm pressure.

Question 4.
A flask P contains 0.5 g mole of oxygen gas. Another flask Q contains 0.4 mole of ozone gas. Which of the two flasks contains greater number of oxygen atoms ?
Answer:
HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules 2

Question 5.
What weight of calcium contains the same number of atoms as are present in 3.2 g of sulphur ?
Answer:
HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules 3

Question 6.
Silicon forms a compound with chlorine in which 5.6 g of silicon is combined with 21.3 g of chlorine..
Calculate the formula of the compound (Atomic mass : Si = 28 : Cl = 35-5).
Answer:
HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules 4
The simplest whole number ratios of different elements are : Si : Cl : : 1 : 3
The formula of the compound = SiCl3.

Question 7:
In magnesium sulphide, the ratio by mass of Mg and S is 3 : 4. What is the ratio of the number of Mg and S atoms ?
Answer:
HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules 5

Hope given HOTS Questions for Class 9 Science Chapter 3 Atoms and Molecules are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.