Question

10.A charge +q is fixed to each of three corners of a square.On the empty corner a charge Q is placed such that there is no net electrostatic force acting on the diagonally opposite charge.Then

Answer 1

ΔCDE|=14×23×24=4|ΔCDE|=14×23×24=4

|ΔAEF|=34×12×24=12×24=9|ΔAEF|=34×12×24=12×24=9

|ΔBDF|=13×12×24=4|ΔBDF|=13×12×24=4

So the sum of the corner triangles is 1717, leaving 77 for the required triangle.