Potential difference charge and Energy - Equation

[pat666]

Homework Statement

If the potential difference between a cloud and the ground is about 13MV , how much charge is transferred in a lightning bolt that releases 1.3GJ of energy?

Homework Equations

The Attempt at a Solution

1st can someone check my conversion - P.d=13*10^6V and E=13*10^9J
The main problem I have is that I don't know the equation relating E, P.V and q or if it exists... can someone please give me a hand... thanks

 

[pat666]

Don't worry - solved