Physics Homework on Electric Potential

1. what is electric potential? how different is gravitational potential energy from electric potential energy?

2. define the electric potential energy between two point charges q and qo using an equation.

3. what is the relationship between potential energy and work done by the force of an electric field?

4. in a uniform electric field, what happens to the potential energy when a positive charge moves in the direction of E? how about when it moves opposite to E?