During a thunder storm, movement of water molecules within clouds creates friction which causes the bottom of the clouds to become negatively charged. this means that the bottom of the cloud and the ground begin to act like parallel plates. once the electric field between the clouds and the ground becomes larger than 3.0 x 10^6 n/c, lightning will strike.

a. if the bottom of the cloud is 150 m above the ground, determine the electric potential difference between the ground and the cloud.