Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : The binding energy per nucleon is found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170.
Reason (R) : Nuclear force is long range.
In the light of the above statements, choose the correct answer from the options given below :
Assertion (A) : The binding energy per nucleon is found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170.
Reason (R) : Nuclear force is long range.
In the light of the above statements, choose the correct answer from the options given below :
- (A)(A) is false but (R) is true
- (B)(A) is true but (R) is false✓ Correct
- (C)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (D)Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
Answer: (B)
Solution
The binding energy per nucleon curve is nearly flat, around MeV per nucleon, for mass numbers roughly between and , so Assertion (A) is correct.
The nuclear force is, however, a short-range force acting only over a few femtometres — this short range is exactly why the binding energy per nucleon saturates instead of continuing to rise with . Reason (R), which calls the nuclear force long-range, is therefore false.
(A) is true but (R) is false.
The nuclear force is, however, a short-range force acting only over a few femtometres — this short range is exactly why the binding energy per nucleon saturates instead of continuing to rise with . Reason (R), which calls the nuclear force long-range, is therefore false.
(A) is true but (R) is false.
JEE Main · 2025 · 23 Jan 2025 · Shift 2 · Single correct option