Two protons are positioned at a separation of 10 nm . Let F_n and...

The nuclear force is a short-range force, effective only up to distances of the order of a few femtometers ($1 \text{ fm} = 10^{-15} \text{ m}$).

The given separation between the protons is $10 \text{ nm} = 10 \times 10^{-9} \text{ m} = 10^{-8} \text{ m}$.

At this distance, the nuclear force $F_n$ is negligibly small and practically zero.

The electromagnetic force $F_e$ is a long-range force and varies as $\dfrac{1}{r^2}$. At $10 \text{ nm}$, it has a finite, non-zero value.

Therefore, at a separation of $10 \text{ nm}$, $F_e \gg F_n$.