Two nuclei have their mass numbers in the ratio of `1:3`. The ratio of their nuclear densities would be

Explanation

To solve the problem of finding the ratio of nuclear densities of two nuclei with mass numbers in the ratio of 1:3, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nuclear Density**:
Nuclear density (D) is defined as the mass (m) of the nucleus divided by its volume (V). The formula for density is:
\[
D = \frac{m}{V}
...