Question:
A test charge q is made to move in the electric field of a point charge Q along two different closed paths. First path has sections along and perpendicular to lines of the electric field, the second path is a rectangular loop of the same area as the first loop. How does the work done compare in the two cases?
Solution:
Work done is zero in both the cases. The work done by the electric force on the charge is in the closed-loop which is equal to zero.