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Four statements are given (A is mass number):
A. The volume of a nucleus is proportional to A^1/3.
B. The volume of a nucleus is proportional to A.
C. The difference in mass of an atom and its nucleus is called the mass defect.
D. The difference in mass of a nucleus and its constituents is called the mass defect.
Choose the correct answer from the options given below:

Asked in NEET 2026 · Nuclear radius and density

• (1) A and D are true, but B and C are false
• (2) B and D are true, but A and C are false
• (3) B and C are true, but A and D are false
• (4) A and C are true, but B and D are false

Step-by-step solution

Why the other options are wrong

• (1) Takes the law for the radius, R∝ A^1/3, as the law for the volume; the volume goes as R³∝ A.
• (3) C describes the mass of the electrons (less their binding), not the mass defect; the mass defect compares the nucleus with its free protons and neutrons.
• (4) Both slips at once: uses A^1/3 for the volume and calls the electrons' mass the mass defect.

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