Question

Regarding a nucleus, choose the correct options :

• A. Density of a nucleus is directly proportional to mass number A.
• B. Nucleus radius $\propto A^{1/3}$
• C. Nuclear forces are dependent on the nature of nucleons.
• D. Nuclear forces are short range forces.

Answer 1

Answer: (B), (D)

The correct options are
B Nucleus radius $\propto A^{1/3}$
D Nuclear forces are short range forces.

Density of nucleus is: $\rho =\frac{A}{\frac{4}{3}\pi R^3}$
The radius of a nucleus, $R=r_0{A}^{1/3},$ so density of nucleus is independent of A and $R\propto {}^3\sqrt{A}$
The nuclear force is a short-range force because the distance between the nucleon is less than $0.7$ fermi (then the force is repulsive) and if greater than $10.7$ fermi (the force is attractive).