Nuclear Physics is an important branch of physics that studies the structure, properties, and behavior of the atomic nucleus. It explains how protons and neutrons are arranged inside the nucleus and how different nuclei can vary in stability. This chapter also introduces key concepts such as isotopes and radioactivity, which help us understand unstable nuclei and their natural decay process.
In addition, Nuclear Physics covers the idea of half-life, nuclear reactions, and the basic forces that hold the nucleus together. These concepts are essential for understanding nuclear energy production and the powerful changes that occur in nuclear processes.
📥 Download Class 12 Physics Chapter 21 – Nuclear Physics (Punjab Board)
Skip to PDF contentGet complete, well-organized and exam-focused notes designed to help you score high in board exams. These notes are simple, clear, and cover all important topics from the chapter.
📚 What You Will Get in This PDF:
✔ Easy-to-understand chapter explanation
✔ Important definitions & key concepts
✔ MCQs with answers (exam-focused)
✔ Short questions for quick revision
✔ Important long questions for board exams
📥 Download PDF: Download Class 12 Physics Chapter 21
📝 MCQs – Nuclear Physics
1. The binding energy per nucleon is maximum for:
(a) Hydrogen
(b) Iron (Fe) ✅
(c) Uranium
(d) Helium
2. In nuclear fission, the energy released is mainly due to:
(a) Mass defect converted into energy (E = mc²) ✅
(b) Chemical reaction
(c) Electron transitions
(d) Heat conduction
3. Which radiation has the highest penetrating power?
(a) Alpha rays
(b) Beta rays
(c) Gamma rays ✅
(d) Neutrons only
4. The correct sequence of penetrating power is:
(a) γ > β > α
(b) α > β > γ
(c) α > γ > β
(d) β > α > γ
5. In nuclear reactions, mass number is conserved but:
(a) Energy is not conserved
(b) Charge is not conserved
(c) Total energy is conserved (including mass energy) ✅
(d) Neutrons are not conserved
6. The half-life of a radioactive substance depends on:
(a) Temperature and pressure
(b) Chemical state
(c) Nuclear properties only ✅
(d) Volume of sample
7. In nuclear fission, a chain reaction occurs due to:
(a) Release of photons
(b) Emission of neutrons triggering further fission ✅
(c) Electron collisions
(d) Heat loss
8. The most stable nuclei are found in elements having:
(a) Very low mass number
(b) Very high mass number
(c) Intermediate mass number (around iron region) ✅
(d) Only hydrogen isotopes
❓ FAQs – Nuclear Physics (Class 12 Physics Chapter 21)
Q1: What is Nuclear Physics?
Nuclear Physics is the branch of physics that deals with the structure, properties, and behavior of the atomic nucleus.
Q2: What is the atomic nucleus made of?
The atomic nucleus is made up of protons and neutrons, collectively called nucleons.
Q3: What are isotopes?
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
Q4: What is radioactivity?
Radioactivity is the spontaneous emission of radiation from unstable atomic nuclei.
Q5: What is half-life?
Half-life is the time required for half of the radioactive nuclei in a sample to decay.
Q6: What is nuclear fission?
Nuclear fission is the process in which a heavy nucleus splits into two or more lighter nuclei, releasing a large amount of energy.