Question

Assertion: Nuclear binding energy per nucleon is in the order $ -_{4}^{9}Be>_{3}^{7}Li>_{2}^{4}He $ . Reason: Binding energy per nucleon increases linearly with difference in number of neutrons and protons.

• A. If both assertion and reason are true and reason is not the correct explanation of assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of assertion.
• C. If assertion is true but reason is false.
• D. If both assertion and reason are false

Answer 1

Answer: (D)

Both the assertion and reason are wrong. Binding energy is the amount of energy which is released when neutrons and protons add to make nucleus. It depends on the mass defect. Binding energy divided by number of nucleons (i.e. binding energy per nucleon) is a direct measurement of the stability of nucleus. Higher the binding energy per nucleon, higher will be stability of nucleon. Binding energy per nucleon for $ {{\,}_{\text{2}}}\text{H}{{\text{e}}^{\text{4}}} $ is 7.08 MeV, that for $ _{\text{3}}\text{Li} $ is 5.38 MeV and that for $ {{\,}_{4}}\text{B}{{\text{e}}^{9}} $ is.