Are these practice questions for Nuclei based on the CBSE pattern?

Yes. Every practice question is modeled on the CBSE Class 12 - Science Physics exam pattern — including MCQs, assertion-reason questions, and short-answer formats that frequently appear in CBSE papers.

Are the practice questions for Nuclei free?

Yes. Every chapter includes free practice questions for Class 12 - Science students to get you started.

What types of questions are included?

The practice set for Nuclei mainly includes MCQs and CBSE-style short-answer questions, with instant feedback on each answer. For full-length textbook practice, use the NCERT Solutions page.

Are the practice questions suitable for board exam preparation?

Yes. The questions test the same concepts and depth that CBSE asks in board exams. After finishing, also solve the NCERT and NCERT Exemplar exercises for Nuclei for full coverage.

How many practice questions are there for Nuclei?

The number scales with chapter length and concept density. Each chapter typically has 15-50 practice questions across MCQ and short-answer formats.

Nuclei Class 12 Physics Practice Questions with Answers

easy

Evaluate the key properties of the nuclear force and justify why it must be significantly stronger than the electrostatic force for a nucleus to be stable.

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easy

Define the atomic mass unit (u).

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easy

Define nuclear fission and nuclear fusion.

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easy

Calculate the energy equivalent in MeV for a mass of

1.0 \times 10^{-30} \text{ kg}

. (Given

c = 3 \times 10^8 \text{ m/s}

and

1 \text{ MeV} = 1.6 \times 10^{-13} \text{ J}

).

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easy

Recall the empirical formula that relates the radius of a nucleus to its mass number A.

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easy

Identify the number of protons and neutrons in the nucleus of a gold isotope,

{ }_{79}^{197} \text{Au}

.

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easy

Calculate the radius of a

{}_{26}^{56}\text{Fe}

nucleus, given that the constant

R_0 = 1.2 \times 10^{-15} \text{ m}

.

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easy

List the three main types of radioactive decay.

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easy

Propose one key reason why nuclear fusion is often considered a 'cleaner' energy source compared to nuclear fission.

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easy

The mass of a proton is

1.67262 \times 10^{-27} \text{ kg}

. Solve for its mass in atomic mass units (u), given that

1 \text{ u} = 1.660539 \times 10^{-27} \text{ kg}

.

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easy

Describe the composition of a nucleus using the terms atomic number (Z), neutron number (N), and mass number (A).

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easy

The radius of a nucleus is found to be

3.6 \text{ fm}

. If

R_0 = 1.2 \text{ fm}

, calculate the mass number of this nucleus.

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medium

Calculate the energy released in the following fusion reaction:

{}_{1}^{2}\text{H} + {}_{1}^{3}\text{H} \rightarrow {}_{2}^{4}\text{He} + {}_{0}^{1}\text{n}

. Atomic masses are:

m({}_{1}^{2}\text{H}) = 2.014102 \text{ u}

,

m({}_{1}^{3}\text{H}) = 3.016049 \text{ u}

,

m({}_{2}^{4}\text{He}) = 4.002603 \text{ u}

,

m({}_{0}^{1}\text{n}) = 1.008665 \text{ u}

.

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medium

Calculate the approximate radius of the

{ }_{26}^{56} \text{Fe}

nucleus, given that the constant

R_0 = 1.2 \text{ fm}

.

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medium

Formulate a hypothesis to explain why the mass of a stable nucleus is consistently less than the sum of the masses of its individual protons and neutrons. Evaluate this hypothesis using Einstein's mass-energy equivalence principle.

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medium

Analyze the statement: 'The mass of a nucleus is always less than the sum of the masses of its constituent free nucleons.' Explain the physical significance of this mass difference.

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medium

Propose a self-sustaining chain reaction mechanism for the fission of

{}_{92}^{235}U

. Justify why a 'critical mass' is essential to sustain this reaction and evaluate the role of the neutrons produced in the process.

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medium

Compare and contrast nuclear fission and nuclear fusion as sources of energy. Refer to the binding energy per nucleon curve to support your analysis.

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medium

Analyze why a heavy nucleus like Uranium (

{}_{92}^{238}\text{U}

) is unstable, while a medium-sized nucleus like Iron (

{}_{26}^{56}\text{Fe}

) is highly stable, by referring to the binding energy per nucleon curve.

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medium

Compare the nuclear density of a gold nucleus (

{}_{79}^{197}\text{Au}

) with that of an iron nucleus (

{}_{26}^{56}\text{Fe}

). Show your reasoning.

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medium

Apply the concept of mass-energy interconversion to explain why energy is released in a nuclear reaction where the total binding energy of the products is greater than the total binding energy of the reactants.

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medium

Explain the concept of 'mass defect' of a nucleus.

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medium

Summarize three key properties of the nuclear force.

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medium

Summarize the main features observed in the plot of binding energy per nucleon versus mass number A.

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medium

Propose an experimental method to verify the relationship for nuclear radius,

R = R_0 A^{1/3}

. Justify your choice of projectile particles for this experiment.

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medium

Justify why binding energy per nucleon, rather than the total binding energy, is a more appropriate measure for comparing the stability of different nuclei.

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medium

A student claims that since the binding energy per nucleon for Uranium (

A=238

) is

7.6 \text{ MeV}

and for Iron (

A=56

) is

8.75 \text{ MeV}

, Iron must be more radioactive. Critique this statement.

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medium

Calculate the energy equivalent of one atomic mass unit (1 u) in MeV.

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medium

Explain the terms 'isotopes' and 'isobars' with one example for each.

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medium

Recall Einstein's mass-energy equivalence relation and explain its significance in nuclear reactions.

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medium

Critique the feasibility of achieving controlled nuclear fusion at room temperature. Justify your answer by evaluating the role of the Coulomb barrier.

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medium

The nucleus of gold is denoted by

{}_{79}^{197}\text{Au}

. Solve for the number of protons and neutrons in its nucleus. From the following list of nuclides, identify one isotone and one isobar of a different element:

{}_{80}^{197}\text{Hg}

,

{}_{79}^{198}\text{Au}

,

{}_{78}^{196}\text{Pt}

.

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hard

A possible fission reaction for Uranium-235 is

{}_{92}^{235}\text{U} + {}_{0}^{1}\text{n} \rightarrow {}_{54}^{140}\text{Xe} + {}_{38}^{94}\text{Sr} + 2{}_{0}^{1}\text{n}

. Calculate the Q-value for this reaction and analyze whether the reaction is exothermic. Given atomic masses:

m({}_{92}^{235}\text{U}) = 235.04393 \text{ u}

,

m({}_{54}^{140}\text{Xe}) = 139.92164 \text{ u}

,

m({}_{38}^{94}\text{Sr}) = 93.91536 \text{ u}

,

m({}_{0}^{1}\text{n}) = 1.008665 \text{ u}

.

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hard

Calculate the mass defect and binding energy per nucleon for a helium nucleus (

{}_{2}^{4}\text{He}

). Given: mass of helium nucleus

m({}_{2}^{4}\text{He}) = 4.001506 \text{ u}

, mass of proton

m_p = 1.00727 \text{ u}

, and mass of neutron

m_n = 1.00866 \text{ u}

. Use

1 \text{ u} = 931.5 \text{ MeV/c}^2

.

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hard

Design a conceptual model to explain the saturation property of nuclear forces. Justify how your model explains the near-constancy of binding energy per nucleon for nuclei with mass numbers in the range

30 < A < 170

.

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hard

Examine the statement that the nuclear force is short-ranged, using the constancy of the binding energy per nucleon for nuclei with

30 < A < 170

as evidence.

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hard

Explain how both nuclear fission and nuclear fusion processes release energy, with reference to the binding energy per nucleon curve.

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hard

Demonstrate that the density of nuclear matter is nearly constant and independent of the mass number A. Start from the empirical formula for the radius of a nucleus,

R = R_0 A^{1/3}

, and clearly state any assumptions made.

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hard

Critique the statement: 'The density of a Uranium nucleus is significantly greater than that of a Helium nucleus because Uranium is a much heavier element.' Justify your answer by deriving a general expression for nuclear matter density.

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hard

Explain why the density of nuclear matter is nearly constant for all nuclei.

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NucleiClass 12 Physics Practice Questions