Question

Two nucleons are at a separation of $1\, fm$. The net force between them is $F_{1}$, if both neutrons, $F_{2}$ if both are protons and $F_{3}$ if one is a proton and the other is a neutron.

• A. $F_{1} > F_{2} > F_{3}$
• B. $F_{2} > F_{1} > F_{3}$
• C. $F_{1}=F_{3} > F_{2}$
• D. $F_{1}=F_{2} > F_{3}$

Answer 1

Answer: (C)

Nuclear force of attraction between any two nucleons $(n-n$, $p-n, p-n)$ is same. The difference comes up only due to electrostatic force of repulsion between two protons.
$\therefore F_{1}=F_{3} \neq F_{2}$
As $F_{2} < F_{3} > F_{1}$
$\therefore F_{1}=F_{3} >F_{2}$