Question
No work is done in moving test charge over an equipotential surface. Why?
Solution
If, a positive test charge q is moved from point A to B, then,
where, WAB is work done to move charge q from A to B.
Since, two points A and B are on the same equipotential surface,
VB-VA=0
where, WAB is work done to move charge q from A to B.
Since, two points A and B are on the same equipotential surface,
VB-VA=0