Atoms & Nuclei

JEE Main level, single correct, medium

54 of 239

Question 54 of 239

The mass of proton, neutron and helium nucleus are respectively 1.0073u,1.0087uand4.0015u1.0073u,1.0087uand4.0015u. The binding energy of helium nucleus is:

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Answer: (B) 28.4MeV28.4MeV

Given here, mHe=4.0015u{m}_{He}=4.0015u, mp=1.0073u{m}_{p}=1.0073u and mn=1.0087u{m}_{n}=1.0087u.
Mass defect

∆m=2mp+2mn−mHe=2×1.0073+2×1.0087−4.0015=0.0305u∆m=2{m}_{p}+2{m}_{n}-{m}_{He} =2\times 1.0073+2\times 1.0087-4.0015 =0.0305u
Binding energy

E=∆m×931MeV=0.0305×931=28.4MeVE=∆m\times 931MeV =0.0305\times 931 =28.4MeV

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