How much work is done in moving a `500 muC` charge between two points on an equipotential surface?

What is the work done in moving a charge of 10 micro Coulomb between two points on an equipotential surface?

How much work is done in moving a charge of 5C between two points in a circuit having a potential difference of 10 V?

How much work is done to carry 2 c of charge between two points having potential difference of 12V?

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

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