The range of nuclear force is of the order of:

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 10-15 m.
  • 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:

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

EXPLANATION:

• From above it is clear that the range of a nuclear force is of the order of 1 fermi. Therefore option 3 is correct.