Question

Four charges are arranged at the corners of a square ABCD as shown in the figure. If a test charge is placed at the centre, calculate the direction of net force on that charge.

• A. zero
• B. along the diagonal AC
• C. along the diagonal BD
• D. perpendicular to side AB

Answer 1

The correct option is A zero

The forces on the charged particle due to charges at A and C is zero because the charges kept at A and C are equal and opposite. Thus their forces cancel out.
Similarly, the force on the charged particle due to charges at B and D is zero because the charges kept at B and D are equal in magnitude and opposite. Thus these forces cancel out.
The net force is thus zero.