β’οΈ Chapter 20: Atomic & Nuclear Physics β Multiple Choice Questions
Prepared by Muhammad Tayyab, Subject Specialist Physics, Govt Christian High School Daska. Based on PECTAA 2026 syllabus (National Curriculum 2023).
π What's Inside: This chapter covers Rutherford's experiment, atomic number, alpha radiation, radioactive decay, nuclear fission, Einstein's equation, and applications of nuclear radiation. Each MCQ is presented with the correct answer and detailed explanation as per the official PECTAA 2026 Physics curriculum. Perfect for Punjab Boards (Lahore, Gujranwala, Multan, etc.) and all BISE boards across Pakistan.
π Related Resources β Chapter 20
π Short Questions
π Exercise Short Qs
βοΈ Constructed Response
π Long Questions
π Numerical Problems
Atomic and Nuclear Physics covers atomic structure, isotopes, radioactivity, alpha/beta/gamma decay, nuclear fission, fusion, half-life, and carbon dating.
π Multiple Choice Questions (PECTAA 2026)
20.1 What did Rutherford's alpha particle scattering experiment reveal about the structure of the atom?
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Correct Answer: (D) The nucleus is small, dense, and positively charged
Rutherford's experiment showed that most alpha particles passed through (mostly empty space), some deflected (positive nucleus), and few bounced back (dense nucleus).
Rutherford's experiment showed that most alpha particles passed through (mostly empty space), some deflected (positive nucleus), and few bounced back (dense nucleus).
20.2 The atomic number of an element represents:
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Correct Answer: (B) number of protons in the nucleus
The atomic number (Z) represents the number of protons in an atom's nucleus, which uniquely identifies the element.
The atomic number (Z) represents the number of protons in an atom's nucleus, which uniquely identifies the element.
20.3 Which type of radiation is positively charged and consists of two protons and two neutrons?
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Correct Answer: (A) Alpha (Ξ±)
Alpha particles are helium nuclei, consisting of 2 protons and 2 neutrons, carrying a +2e charge.
Alpha particles are helium nuclei, consisting of 2 protons and 2 neutrons, carrying a +2e charge.
20.4 The process by which an unstable nucleus emits radiation and transforms into a more stable nucleus is called:
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Correct Answer: (C) radioactive decay
Radioactive decay is the process in which unstable atoms release radiation to become stable.
Radioactive decay is the process in which unstable atoms release radiation to become stable.
20.5 Nuclear fission involves:
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Correct Answer: (B) splitting heavy atomic nuclei into smaller ones
In fission reaction, a heavy nucleus (like Uranium-235) splits into two smaller nuclei when bombarded by a neutron.
In fission reaction, a heavy nucleus (like Uranium-235) splits into two smaller nuclei when bombarded by a neutron.
20.6 What does Einstein's equation; \(E = mc^2\); explain?
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Correct Answer: (B) The equivalence of mass and energy
Einstein's equation \(E = mc^2\) states that a small amount of mass (m) converts into a large amount of energy (E).
Einstein's equation \(E = mc^2\) states that a small amount of mass (m) converts into a large amount of energy (E).
20.7 Which of the following is a practical application of nuclear radiations?
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Correct Answer: (B) Medical imaging and cancer treatments
Nuclear radiations are used in medicine for imaging and cancer treatment, such as Cobalt-60 in radiotherapy and Iodine-131 in thyroid treatment.
Nuclear radiations are used in medicine for imaging and cancer treatment, such as Cobalt-60 in radiotherapy and Iodine-131 in thyroid treatment.
20.8 What are the potential effects of ionizing nuclear radiation on biological tissues?
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Correct Answer: (B) DNA damage and cancer
Ionizing radiation can alter or damage atoms and molecules, including DNA, leading to mutations and cancer.
Ionizing radiation can alter or damage atoms and molecules, including DNA, leading to mutations and cancer.
βοΈ Key Concepts β Atomic & Nuclear Physics
Atomic Number: \(Z = \text{number of protons}\)
Mass Number: \(A = Z + N\) (protons + neutrons)
Mass-Energy Equivalence: \(E = mc^2\)
Alpha Decay: \(_{Z}^{A}\mathrm{X} \rightarrow _{Z-2}^{A-4}\mathrm{Y} + _{2}^{4}\mathrm{He}\)
Beta Decay: \(_{Z}^{A}\mathrm{X} \rightarrow _{Z+1}^{A}\mathrm{Y} + _{-1}^{0}\beta + \text{Energy}\)
Unit 10Thermal Physics
Unit 11Transfer of Thermal Energy
Unit 12Waves
Unit 13Sound
Unit 14Light
Unit 15Electrostatics
Unit 16Electricity
Unit 17Electromagnetism
Unit 18Electromagnetic Induction & EM Waves
Unit 19Electronics
Unit 20β¨ Atomic and Nuclear Physics
Unit 21Space and Environment
π Complete syllabus coverage for Class 10 Physics (PECTAA 2026) β Units 10 to 21
π‘ Exam Tip:
For board exams, read each question carefully and eliminate obviously wrong options. These MCQs follow the PECTAA 2026 pattern and are prepared by Subject Specialist Muhammad Tayyab.
Created by Hira Science Academy | Aligned with PECTAA 2026 Syllabus