# Electricity from lightning

1. According to the internet, a lightning strike contains about 5 billion joules or 5 GJ. How was this calculated?

2. Another thing: Once the lightning strike a metal grounded rod, a current will flow. What type of that current and how much current? I think it will be a 325 MV current which is the voltage of the lightning. Is that correct?

Edit: after i read a little bit about lightning , i found it was such a big scale , so how about a small electrostatic charge , say from a 1 MV van de graaff generator, i have a spark source ( my CRT TV :D ) and i will buy a multimeter and conduct some experiments , but i need to know what to expect

• Related: physics.stackexchange.com/q/76251/2451 and links therein. – Qmechanic Mar 23 '14 at 17:44
• You may be interested in reading more about electric currents, and how they differ from voltages. Note, in particular, that current is not measured in volts. Otherwise, +1. – Emilio Pisanty Mar 23 '14 at 19:03
• hahahaha :D , i know....what i meant was that the current has a voltage of 325 MV, 325 MV in the clouds and 0 V in the ground – user28324 Mar 23 '14 at 21:13
• Current doesn't have voltage just like speed doesn't have horsepower. They measure different things. Before a lightning strike, there is a huge voltage difference between the clouds and the ground. The presence of the voltage makes the current flow, but at the same time, the flow of the current makes the voltage go away. – Solomon Slow Dec 2 '15 at 1:06