Question

How does the density of the nucleus remain constant over a wide range of nuclei, independent of mass number? Mention any two points.

A. The volume occupied by nucleons remains constant.
B. The number of nucleons increases proportionally with the mass number.
C. The nuclear force acts over short ranges, maintaining a relatively constant density.
D. The density of the nucleus is inversely proportional to the mass number.

Answer 1

The density of the nucleus remains roughly constant across different nuclei because the number of nucleons increases proportionally with the mass number, and the nuclear force maintains a tight packing, thus keeping the volume nearly steady.

Step-by-step explanation:

The density of the nucleus remains constant over a wide range of nuclei, independent of the mass number, mainly because the number of nucleons (protons and neutrons) increases proportionally with the mass number. Essentially, the volume of a nucleus remains roughly constant due to two related reasons:

1. The nuclear force is very strong and acts over short ranges, which effectively holds nucleons in close proximity to each other, resisting both being pulled apart and pushed closer together. This force maintains a relatively constant density across different nuclei.
2. The volume of the nucleus is the sum of the volumes of the nucleons within it, and because these particles are tightly packed, there is very little empty space in the nucleus. Hence, as the mass number increases, the volume only increases marginally, leading to a near-constant density.

Therefore, statements (B) and (C) are the most accurate in explaining why the density of the nucleus is approximately constant across different nuclei.