Q.Which one of the following fundamental forces in nature binds protons and neutrons in a nucleus ?

Physics recognises only four fundamental forces of nature; tension is a macroscopic contact force that ultimately arises from electromagnetic interactions between atoms, so it is not itself fundamental.

The four fundamental forces of nature, as classified in physics, are:

1. Gravitational force - acts between any two masses, always attractive, weakest of the four.
2. Electromagnetic force - acts between charges, can be attractive or repulsive.
3. Strong nuclear force - binds protons and neutrons inside the nucleus, strongest of the four but short-ranged.
4. Weak nuclear force - responsible for processes like beta decay. …

Of the four options, only Gravitational Force is a fundamental force of nature; Elastic, Restoring and Frictional forces are all contact forces that arise from electromagnetic interactions between atoms and molecules.

Physics recognises a small number of truly fundamental forces from which every other force in nature can, in principle, be derived: the gravitational force, the electromagnetic force, the strong nuclear force and the weak nuclear force.

• Gravitational force acts between any two masses and cannot be reduced to any more basic interaction — it is fundamental. …

The strong nuclear force is the fundamental force that binds protons and neutrons together inside the nucleus.

Of the four fundamental forces of nature — gravitational, electromagnetic, strong nuclear and weak nuclear — the strong nuclear force acts between nucleons (protons and neutrons) over the very short range of the nucleus (~10⁻¹⁵ m). It is strongly attractive and charge-independent (it acts equally between p-p, n-n and p-n pairs), so it is able to overcome the electrostatic repulsion between the closely-packed positive protons and hold the nucleus together. …

TRUE — among the four fundamental forces of nature, gravity is by far the weakest, so even the weak nuclear force is stronger than it.

The four fundamental forces of nature, in increasing order of strength, are:

1. Gravitational force — relative strength ≈ 10⁻³⁸ (weakest of all).
2. Weak nuclear force — relative strength ≈ 10⁻¹³.
3. Electromagnetic force — relative strength ≈ 10⁻².
4. Strong nuclear force — relative strength ≈ 1 (strongest). …