question_answer

Positive and negative charges of equal magnitude are kept at \[\left( 0,\,0,\,\frac{a}{2} \right)\]and \[\left( 0,\,0,\,\frac{-a}{2} \right)\] respectively. The work done by the electric field when another positive point charge is moved from (-0,0,0) to (0, a, 0) is:

A) positive              

B) negative

C) zero

D) depends on the path connecting the initial and final positions

Correct Answer: C

Solution :

(c) zero It can be seen that potential at the points both A and B are zero. When the charge is moved from A to B, work done by the electric field on the charge will be zero.