It's about 6 minutes, as I seem to recall. Sort of the time for the earth to go into shadow darkness when there's an eclipse ???
B. By vibrations in wires or strings
The used work of energy output is 496*2.1=1041.6 J. And the actual work of energy output is 1127*0.85=957.95 J. The percentage efficiency is 957.95/1041.6*100%=91.97 %.
It's negative electric charge
