The net force on charge placed is given by the superposition of forces of the charges placed at other cornersForce on D due to A:F= Kq^2/r^2Similarly, force on D due to C is:F= kq^2/r^2Force on D due to B is:F= kq^2/2r^2Because the distance of diagonal is ✓2rNow apply superposition of charges to get the result:F(due to A and C):F= kq^2✓2/r^2We will add this force to force of BF+ F(B) = kq^2/r^2 (✓2+1/2)N ...(Answer)

Calculation of Force on Charge

- When charges q are placed at the corners A, B, C, and D of the square of length a, the force on any one of the charges can be calculated using Coulomb's law.

- Coulomb's law states that the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

- In this case, the charges at the corners A, B, C, and D will exert a force on each other due to their presence.

Force Calculation

- The force on any one of the charges can be calculated by considering the forces from the other three charges.

- Since the charges are placed at the corners of a square, the distances between them are equal, which makes the forces exerted by them equal in magnitude.

- The net force on the charge will be the vector sum of the forces from the other three charges.

Resultant Force

- Due to the symmetry of the square and the equal magnitudes of the charges, the forces from opposite charges will cancel each other out.

- As a result, the net force on the charge will be zero, and there will be no resultant force acting on the charge.

- This is because the forces on the charge due to the other charges will be equal in magnitude and opposite in direction, leading to a balanced system.

Therefore, the magnitude of the force on the charge will be zero when charges q are placed at the four corners A, B, C, D of a square of length a.