Why different charges attract each other?

Question

I have a simple question that why positive and negative charges attract each other? We always learn that there is always a reason behind this. Can anyone tell me the actual reason behind this?

Answer 1

Yes, the reason is that the energy of the system decreases with decrease in distance. The potential energy between a positive charge $q_1$ and a negative charge $q_2$ is given by $U=\frac{Kq_1q_2}{r^2}$. Now since $$q_2<0, q_1>0\Rightarrow U=\frac{Kq_1q_2}{r^2}<0$$. Hence as $r_2$ decreases, $U$ gets smaller. The smaller the potential energy $U$, the stabler the system, hence the system tries to get closer by attracting each other thus forming a stabler configuration.