R4RIN – MCQs, Mock Tests | NCERT Class 12 MCQ Questions for Class 12 Physics Chapter 12 Atoms

An atom stays in an excited state for about:

1. 10 micro seconds
2. 10 milli seconds
3. 10 nano seconds
4. 10 seconds

✅ Correct Answer: 3

The energy equivalent to one atomic mass unit is :

1. 1.6 × 10-19 J
2. 6.02 × 1023 J
3. 9.31 MeV
4. 931 MeV

✅ Correct Answer: 4

Who explained the splitting of special lines in magnetic field?

1. Zeeman
2. Bohr
3. Summerfield
4. Einstein

✅ Correct Answer: 1

The mass of a neutron is:

1. 1.00866 u
2. 1.0866 u
3. 1.866 u
4. 0.1866 u

✅ Correct Answer: 1

Isobars have the same:

1. A
2. Z
3. N
4. All the above

✅ Correct Answer: 1

Isotones have the same:

1. A
2. Z
3. Neutron
4. All the above

✅ Correct Answer: 3

Half-life of a substance depends on:

1. pressure
2. temperature
3. density
4. None of the these

✅ Correct Answer: 4

The concept of electron spin was introduced by:

1. Becquerel
2. Goudsmit
3. Millikan
4. Uhlenbeek and Goudsmit

✅ Correct Answer: 4

The principle that a quantum orbital cannot be occupied by more than two electrons was given by:

1. Pauli
2. Millikan
3. Hund
4. None of the above

✅ Correct Answer: 1

For ionization of excited Hydrogen atom, the, required energy is:

1. a little less than 13.6
2. equal to 13.6
3. more than 13.6
4. 3.4 or less

✅ Correct Answer: 4

Artificial radioactivity was discovered by:

1. Joliot
2. Becquerel
3. Pauli
4. None of the above

✅ Correct Answer: 1

P-decay produces:

1. isobars
2. isotopes
3. isotones
4. All the above

✅ Correct Answer: 1

Natural radioactivity was discovered by:

1. Joliot
2. Becquerel
3. Pauli
4. None of the above

✅ Correct Answer: 2

Transmutation of nuclei was discovered by:

1. Rutherford
2. Becquerel
3. Pauli
4. None of the above

✅ Correct Answer: 1

The energy equivalent to mass defect is called :

1. binding energy
2. internal energy
3. external energy
4. enthalpy

✅ Correct Answer: 1

The total energy that will be released if a nucleus is built from its constituents is called the:

1. binding energy of the nucleus
2. binding energy of the solid
3. binding energy of the atom
4. None of the above

✅ Correct Answer: 1

The binding energy of 42He is about:

1. 28.3 eV
2. 28.3 MeV
3. 28.3 J
4. 2.83 MeV

✅ Correct Answer: 2

The binding energy of a deuteron is about:

1. 2.22 MeV
2. 2.22 J
3. 2.22 eV
4. None of the these

✅ Correct Answer: 2