Question

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 practically independent of the atomic number for nuclei of mass number in the range 30 to 170. 
Reason R : Nuclear force is short ranged. 
In the light of the above statements, choose the correct answer from the options given below:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The Correct Option is A

Assertion (A): The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range 30 to 170. This is true because for medium and heavy nuclei, the binding energy per nucleon remains approximately constant and stable in this mass range.

Reason (R): Nuclear force is short-ranged. This is true because nuclear forces act only within a very short range (of the order of a few femtometers) and are responsible for binding nucleons together. Since the stability of the binding energy per nucleon is a consequence of the short-ranged nature of nuclear forces, the reason (R) correctly explains the assertion (A). 

Thus, the correct answer is \( \boxed{(1)} \).