During a particular thunderstorm, the electric potential difference between a cloud and the ground is Vcloud - Vground = 4.0 x 10^8 V, with the cloud being at the higher potential. What is the change in an electron's electric potential energy when the electron moves from the ground to the cloud? I have no idea how to do this problem. Haven't done electric circuits in a year. Any tips or suggestions or formulas to start me off? I was thinking since the number given is change in Potential...can we use a potential formula like V = kq/r? Im not sure what applies here. Any tips at all would be really appreciated, thank you.