Question

From the statements given below :
(A) The angular momentum of an electron in nth orbit is an integral multiple of h.
(B) Nuclear forces do not obey inverse square law.
(C) Nuclear forces are spin dependent.
(D) Nuclear forces are central and charge independent.
(E) Stability of nucleus is inversely proportional to the value of packing fraction.
Choose the correct answer from the options given below :

• A. (A), (B), (C), (D) only
• B. (A), (C), (D), (E) only
• C. (A), (B), (C), (E) only
• D. (B), (C), (D), (E) only

Answer 1

Answer: (C)

(A), (B), (C), (E) only

Answer 2

Let’s analyze each statement:

Statement (A)

The angular momentum of an electron in the $n^{th}$ orbit being an integral multiple of $h$ is a true statement. This is based on Bohr’s quantization condition for angular momentum:

$L = n\hbar, \quad \text{where } \hbar = \frac{h}{2\pi} \text{ and } n \in \mathbb{Z}$

Statement (B)

Nuclear forces do not obey the inverse square law. This is true as nuclear forces are short- ranged and much more complex compared to the inverse-square law of gravitational or electrostatic forces.

Statement (C)

Nuclear forces are spin-dependent. This is true, as the nature of nuclear forces changes with the relative spin orientations of nucleons.

Statement (D)

Nuclear forces are central and charge-independent. This statement is false. While nuclear forces are largely charge-independent, they are not purely central forces since they exhibit a dependence on other factors like spin.

Statement (E)

The stability of the nucleus being inversely proportional to the value of the packing fraction is false. The packing fraction, defined as the binding energy per nucleon, is a measure of nuclear stability, and a lower packing fraction generally indicates lower stability, not higher.

Conclusion

The correct statements are (A), (B), (C), and (E). Therefore, the correct option is:

(3) (A), (B), (C), (E) only