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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