Question

Four similar point charges q are located at the vertices of a regular tetrahedron of edge length

a. the interaction energy of the system of charges is

Answer 1

Since the charges are similar they have potential energy which is stored to do work.
The expression is given by,
$u = k \times {q}^{2} \div {r}^{2}$

Answer 2

Answer:

There are 4 charges given  and taking 2 charges

So, there will be 6 case

and by using formula  kq^2/a

.:, energy of 6 = 6kq^2/a

                        6kq^2/4πε0a