Question

A point charge of 5 µC is moved against a potential difference of + 20 V. What is the work done by the force moving the charge?

Answer 1

If potential difference between two points is V, it means that you do V amount of work to transfer a unit positive charge between them.

Here, you do 20 joules of work to transfer a unit positive charge across. You should be able to work it for a 5 micro coulomb charge.