Electric Charges and Fields — Physics STD 12 Science — Question

2. Only nuclear

Explanation:

CONCEPT:

Strong nuclear force: The strong attractive force which binds together the protons and neutrons in a nucleus is called a strong nuclear force.

• This force cannot be an electrostatic force because positively charged protons strongly repel each other at such a small separation of the order 10^-15m.
• This strong nuclear force is the strongest of all the fundamental forces, about 100 times stronger than the electromagnetic force.

Important properties of the strong nuclear force:

• It is the strongest interaction known in nature, which is about 1038 times stronger than the gravitational force.
• It is a short-range force that operates only over the size of the nucleus (= 10^-15m).
• It is basically an attractive force but becomes repulsive when the distance between the nucleons becomes less than 0.5 fermi (1 fermi = 10^-15m).
• It varies inversely with some higher power (> 2) of distance.
• It is a non-central and non-conservative force. 

From the above, it is clear that the force between a neutron and a proton inside the nucleus is only nuclear attractive.