Question

Two nucleons are at a separation of $1 \times 10^{-15} m$. The net force between them is $F _{1},$ if both are neutrons, $F _{2}$ if both are protons and $F _{3}$ if one is a proton and other is a neutron. In such a case:

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

Answer 1

Answer: (B)

Nuclear forces are the strong forces of attraction which hold together the nucleons (neutrons and protons) in the tiny nucleus of an atom, inspite of strong electrostatic forces of repulsion between protons. Nuclear forces act between a pair of neutrons, a pair of protons and also between a neutron, proton pair with the same strength. This shows that nuclear forces are independent of charge. The attractive nuclear force is the same for any pair of nucleons. Thus $F 1= F _3$ when there are no electrostatic forces, but $F 2$ = attractive nuclear force $-$ repulsive electrostatic force Hence $F _3= F _1 > F _2$