What are the major differences between the four fundamental forces?
The major differences between the four fundamental forces are their relative strengths and the range over which they act.
The four fundamental forces are the strong nuclear force, the electromagnetic force, the weak nuclear force and gravitational force.
Strong Nuclear Force is the strongest of them. It is responsible for holding the nucleus of atoms together despite the huge repulsion between the similar charges of protons in the nucleus. Protons and neutrons are made up of three quarks held together by the color confinement force. The strong force can therefore be regarded as the residual color force of each proton and neutron. This explains why the strong force is so short-ranged.
Electromagnetic Force is the second strongest fundamental force. Electricity and magnetism was thought of to be two separate forces. They were united by James Clerk Maxwell in 1873 as the Electromagnetic force. It has infinite range, but follows the inverse square law and is repulsive between like charges, so its strength diminishes quickly with increasing distance. It is responsible for holding atoms and molecules together. It is so strong at atomic levels that it dominates the other three forces.
Weak Nuclear Force involves the exchange of W and Z bosons. It has a very short range, typically between
Gravitational Force is the weakest of all the fundamental forces. However, it is the most dominant force due to its long range. It follows the inverse square law like electromagnetic force, however, it is always attractive and hence is not cancelled out.