Four charges are arranged at the corners of a square `ABCD`, as shown in the adjoining figure, The force on a positive charge kept at the centre `O` is

Options

A. Zero
B. Along the diagonal AC
C. Along the diagonal BD
D. Perpendicular to side AB

Answer

C

Explanation

Put a unit +ve charge at point O.
The resulting force due to the charge placed at point A and C is zero. And resulting force due to B and D is towards D along the diagonal BD.