Class 12 Physics MCQ Chapter 13 Nuclei English Medium
Build a strong foundation in nuclear physics with our Class 12 Physics MCQ Chapter 13 Nuclei English Medium question bank. This article offers a carefully compiled collection of multiple-choice questions (MCQs) with answers, helping AHSEC Higher Secondary students prepare effectively for examinations and strengthen their understanding of key concepts.
The chapter Nuclei explores the structure and properties of atomic nuclei, one of the most fascinating areas of modern physics. Students will learn about nuclear composition, atomic mass, isotopes, isobars, binding energy, mass-energy equivalence, radioactivity, radioactive decay laws, nuclear fission, nuclear fusion, and their practical applications. These topics are frequently included in AHSEC board examinations and are essential for understanding the principles of nuclear science.
All MCQs are developed according to the latest AHSEC syllabus and exam pattern, ensuring students practice relevant and high-scoring questions. Regular practice of these objective questions helps improve conceptual clarity, problem-solving ability, and exam confidence.
Whether you are revising important formulas or preparing for the AHSEC Higher Secondary Final Examination, these Chapter 13 MCQ solutions will help you master the chapter and achieve better results in Physics.
PART II
Class 12 Physics MCQ Chapter 13 Nuclei English Medium
VSA & MCQ
I. Very Short Answer Questions
Q. What is a nucleus?
Ans: The central core of an atom containing protons and neutrons.
Q. What are nucleons?
Ans: Protons and neutrons.
Q. What is atomic number (Z)?
Ans: Number of protons in nucleus.
Q. What is mass number (A)?
Ans: Total number of nucleons, A = Z + N.
Q. What are isotopes?
Ans: Same Z but different A.
Q. What are isobars?
Ans: Same A but different Z.
Q. What are isotones?
Ans: Same number of neutrons.
Q. What is nuclear radius?
Ans: R = R₀A^(1/3).
Q. What is value of R₀?
Ans: R₀ ≈ 1.3 × 10⁻¹⁵ m.
Q. What is nuclear density?
Ans: Nearly constant for all nuclei.
Q. What is binding energy?
Ans: Energy required to separate nucleons.
Q. What is mass defect?
Ans: Difference between mass of nucleons and nucleus.
Q. What is relation for binding energy?
Ans: E = Δmc².
Q. What is packing fraction?
Ans: (Mass number − atomic mass) / mass number.
Q. What is nuclear force?
Ans: Strong force binding nucleons.
Q. What are properties of nuclear force?
Ans: Short range, strong, charge independent.
Q. What is radioactivity?
Ans: Spontaneous emission of radiation.
Q. What are types of decay?
Ans: Alpha, beta, gamma.
Q. What is alpha decay?
Ans: Emission of helium nucleus.
Q. What is beta decay?
Ans: Emission of electron or positron.
Q. What is gamma decay?
Ans: Emission of high energy photon.
Q. What is half-life?
Ans: Time for half nuclei to decay.
Q. What is decay law?
Ans: N = N₀e^(−λt).
Q. What is decay constant?
Ans: Probability of decay per unit time.
Q. What is activity?
Ans: Rate of decay, A = λN.
Q. What is unit of activity?
Ans: Becquerel (Bq).
Q. What is fission?
Ans: Splitting of heavy nucleus.
Q. What is fusion?
Ans: Combining of light nuclei.
Q. What is chain reaction?
Ans: Self-sustaining nuclear reaction.
Q. What is nuclear reactor?
Ans: Device for controlled fission.
II. Multiple Choice Questions
Q. Nucleus contains:
(a) Electrons
(b) Protons and neutrons
(c) Only protons
(d) Only neutrons
Ans: (b)
Q. Mass number is:
(a) Z
(b) N
(c) Z + N
(d) Z − N
Ans: (c)
Q. Isotopes have same:
(a) A
(b) Z
(c) N
(d) Mass
Ans: (b)
Q. Binding energy is due to:
(a) Electric force
(b) Nuclear force
(c) Gravity
(d) Friction
Ans: (b)
Q. Alpha particle is:
(a) Electron
(b) Proton
(c) Helium nucleus
(d) Photon
Ans: (c)
Q. Beta particle is:
(a) Electron
(b) Proton
(c) Neutron
(d) Photon
Ans: (a)
Q. Gamma rays are:
(a) Particles
(b) Waves
(c) Both
(d) None
Ans: (b)
Q. Half-life depends on:
(a) Amount
(b) Temperature
(c) Decay constant
(d) Pressure
Ans: (c)
Q. Fission occurs in:
(a) Light nuclei
(b) Heavy nuclei
(c) All
(d) None
Ans: (b)
Q. Fusion occurs in:
(a) Heavy nuclei
(b) Light nuclei
(c) All
(d) None
Ans: (b)
Q. Assertion: Nuclear density is nearly constant. Reason: Radius depends on
A^(1/3).
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Binding energy stabilizes nucleus. Reason: Higher binding energy means more stability.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Radioactivity is spontaneous. Reason: Independent of external conditions.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Half-life is constant. Reason: Depends only on decay constant.
(a) Both true, reason incorrect
(b) Both true, reason correct
(c) Assertion true, reason false
(d) Both false
Ans: (b)
Q. Assertion: Fission releases energy. Reason: Mass converts to energy.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Fusion requires high temperature. Reason: Overcome repulsion.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Gamma rays have no charge. Reason: They are photons.
(a) Assertion true, reason false
(b) Both true, reason incorrect
(c) Both true, reason correct
(d) Both false
Ans: (c).
