Question

Three charges Q, +q and +q are placed at the vertices of an equilateral triangle of side l as shown in the figure. If the net electrostatic energy of the system is zero, then Q is equal to

Answer 1

Answer:

If net electrostatic energy is zero,

then net electrostatic force will also be zero

That is, F1+F2+F3 = 0

F1= kQq/l^2

F2 = kQq/l^2

F3 =kqq/l^2

So Solving this,

2Q+q = 0

Q = -q/2