If the mass number of a nucleus becomes 8 times its original value, its surface area becomes:
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Question

If the mass number of a nucleus becomes 8 times its original value, its surface area becomes:

G1 Physics · Accepted Answer

Nuclear radius varies as R ∝ A¹ᐟ³. Surface area varies as S ∝ R². Therefore, S ∝ A²ᐟ³. If A′ = 8A, S′/S = 8²ᐟ³ = (2³)^(2/3) = 2² = 4. Hence the surface area becomes 4 times. Correct option: B.