why do unlike charges attract each other and like charges repel each other and is this force exchange type like gravitational and nuclear forces

Dear Sohail,

Every system has a tendency to lower it's energy.

For a system of 2 like/unlike charges (q1,q2), the energy of the system is given by the equation

For U to be minimum, r should be maximum, everything else kept constant.
therefore, like charges move away to increase r.

Incase of unlike charges one will be negetive and other positive. Let q1 be negetive, so U=k(-q1)(q2)/r
Now, for U to be minimum, r should be minimum so charges attract.
Hence like charges repel and unlike attract.

Thank you