Work done in moving a positive charge on an equipotential surafce is

No work is done in moving a test charge over an equipotential surface, why?

The amount of work done to move a positive point charge q on an equipotential surface of 1000 V relative to that on an equipotential surface of 10 V is

Assertion(A): A point charge q is rotated along a circle around another point charge Q .The work done by electric field on the field on the rotating charge in half revolution is zero. Reason (R ) :No work is done to move a charge on an equipotential line or surface.

A sphere is constructed around a positive point charge q. The work done in moving a unit positive charge on this sphere is numerically equal to

Work done in moving a positive charge from the centre of a hollow uniformly charged sphere to its surface is zero. Does it imply that the potential is zero inside the sphere?

5 J of work is done in moving a positive charge of 0.5C between two points. What is the potential difference between these points ?