Lightning occurs when there is a breakdown in the electrical insulating properties of air. That is, the potential difference between the ground and a cloud is so great that it overcomes the fact that air usually a pretty good insulator. Air begins to conduct at a potential difference of approximately \(3 \times 10^6\text{ V/m}\).
A typical height for a cloud to ground lightning strike is 1 km.
What is the total voltage difference between the cloud and the ground right before the lightning strike in Volts?
by
David Mattingly
