Four equal point charges of magnitude are fixed at the four corners and of a square…
PHYSICS · Subjective · CBSE · Physics · Electric Charges and Fields · Electric Charges and Fields
Problem
Four equal point charges of magnitude +q are fixed at the four corners A,B,C, and D of a square of side a that lies in the xy-plane with its centre at the origin.
(i) Define an electric field at a point in space.
(ii) State the principle that allows the determination of the net electric field at the centre of the square due to the four charges.
(iii) Using suitable reasoning, explain why the net electric field at the centre of the square is zero.
(iv) If the charge at corner D is replaced by −q while the other three charges remain +q, predict qualitatively the direction of the net electric field at the centre and justify your answer.