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The question is like this:

8 charges of magnitude q and different sighs are placed at corners of a cube of side a.

Find the work done in taking them far away from each other.

U = kq

W = ΔU

First i found out the potential energy of a +q charge

U = -3kq

and the same comes out to be for -q charge (of course)

So for 1 charge,

W = U

W = 0 - ( -3kq

W = 3kq

So work done for 8 charges = 8W ... Right?

But its wrong.

Some help please.

8 charges of magnitude q and different sighs are placed at corners of a cube of side a.

Find the work done in taking them far away from each other.

## Homework Equations

U = kq

_{1}q_{2}/rW = ΔU

## The Attempt at a Solution

First i found out the potential energy of a +q charge

U = -3kq

^{2}/a + 3kq^{2}/√2a - Kq^{2}/√3aand the same comes out to be for -q charge (of course)

So for 1 charge,

W = U

_{f}- U_{i}W = 0 - ( -3kq

^{2}/a + 3kq^{2}/√2a - Kq^{2}/√3a )W = 3kq

^{2}/a - 3kq^{2}/√2a + Kq^{2}/√3aSo work done for 8 charges = 8W ... Right?

But its wrong.

Some help please.