Check the below NCERT MCQ Questions for Class 12 Physics Chapter 12 Atoms with Answers Pdf free download. MCQ Questions for Class 12 Physics with Answers were prepared based on the latest exam pattern. We have provided Atoms Class 12 Physics MCQs Questions with Answers to help students understand the concept very well.

Atoms Class 12 MCQs Questions with Answers

Question 1.
An atom stays in an excited state for about:
(a) 10 micro seconds
(b) 10 milli seconds
(c) 10 nano seconds
(d) 10 seconds

Answer

Answer: (c) 10 nano seconds


Question 2.
The energy equivalent to one atomic mass unit is :
(a) 1.6 × 10-19 J
(b) 6.02 × 1023 J
(c) 9.31 MeV
(d) 931 MeV

Answer

Answer: (d) 931 MeV


Question 3.
Who explained the splitting of special lines in magnetic field?
(a) Zeeman
(b) Bohr
(c) Summerfield
(d) Einstein

Answer

Answer: (a) Zeeman


Question 4.
The mass of a neutron is:
(a) 1.00866 u
(b) 1.0866 u
(c) 1.866 u
(d) 0.1866 u

Answer

Answer: (a) 1.00866 u


Question 5.
Isobars have the same:
(a) A
(b) Z
(c) N
(d) All the above

Answer

Answer: (a) A


Question 6.
Isotones have the same:
(a) A
(b) Z
(c) N
(d) All the above

Answer

Answer: (c) N


Question 7.
Half-life of a substance depends on:
(a) pressure
(b) temperature
(c) density
(d) None of these

Answer

Answer: (d) None of these


Question 8.
The concept of electron spin was introduced by:
(a) Becquerel
(b) Goudsmit
(c) Millikan
(d) Uhlenbeek and Goudsmit

Answer

Answer: (d) Uhlenbeek and Goudsmit


Question 9.
The principle that a quantum orbital cannot be occupied by more than two electrons was given by:
(a) Pauli
(b) Millikan
(c) Hund
(d) None of these

Answer

Answer: (a) Pauli


Question 10.
For ionization of excited Hydrogen atom, the, required energy is:
(a) a little less than 13.6
(b) equal to 13.6
(c) more than 13.6
(d) 3.4 or less

Answer

Answer: (d) 3.4 or less


Question 11.
According to Bohr’s theory of hydrogen atom, the radius r of stationary orbit are related to principal quantum number n as:
(a) rg ∝ \(\frac{1}{n^2}\)
(b) rg ∝ \(\frac{1}{n}\)
(c) rg ∝ n
(d) rg ∝ n²

Answer

Answer: (d) rg ∝ n²


Question 12.
Fg and Fe represents the gravitational and electrostatic force respectively between two electrons situated at some distance the ratio \(\frac{F_g}{F_e}\) is if the order of:
(a) 9.8
(b) 109
(c) 1042
(d) 10-42

Answer

Answer: (d) 10-42


Question 13.
Artificial radioactivity was discovered by:
(a) Joliot
(b) Becquerel
(c) Pauli
(d) None of these

Answer

Answer: (a) Joliot


Question 14.
P-decay produces:
(a) isobars
(b) isotopes
(c) isotones
(d) All the above

Answer

Answer: (a) isobars


Question 15.
Natural radioactivity was discovered by:
(a) Joliot
(b) Becquerel
(c) Pauli
(d) None of these

Answer

Answer: (b) Becquerel


Question 16.
Transmutation of nuclei was discovered by:
(a) Rutherford
(b) Becquerel
(c) Pauli
(d) None of these

Answer

Answer: (a) Rutherford


Question 17.
The energy equivalent to mass defect is called :
(a) binding energy
(b) internal energy
(c) external energy
(d) enthalpy

Answer

Answer: (a) binding energy


Question 18.
The total energy that will be released if a nucleus is built from its constituents is called the:
(a) binding energy of the nucleus
(b) binding energy of the solid
(c) binding energy of the atom
(d) None of these

Answer

Answer: (a) binding energy of the nucleus


Question 19.
The binding energy of \(_{2}^{4}\)He is about:
(a) 28.3 eV
(b) 28.3 MeV
(c) 28.3 J
(d) 2.83 MeV

Answer

Answer: (b) 28.3 MeV


Question 20.
The binding energy of a deuteron is about:
(a) 2.22 MeV
(b) 2.22 J
(c) 2.22 eV
(d) None of these

Answer

Answer: (a) 2.22 MeV


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