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 :

<p>Let's analyze both statements:</p> <p>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.”</p> <p><p>In fact, for nuclei in this mass range, the binding energy per nucleon is nearly constant (around 7–8 MeV per nucleon). This is because the attractive nuclear force saturates, leading to a relatively uniform binding energy per nucleon in medium to heavy nuclei.</p></p> <p><p>Therefore, Assertion (A) is true.</p></p> <p>Reason (R): “Nuclear force is long range.”</p> <p><p>The nuclear force (or strong force) that holds the nucleons (protons and neutrons) together is actually very short-ranged. Its effective range is approximately 1 to 3 femtometers (fm), after which the force rapidly decreases.</p></p> <p><p>Hence, Reason (R) is false.</p></p> <p>Since the assertion is correct and the reason is incorrect, the correct answer is:</p> <p>Option A: (A) is true but (R) is false.</p>