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Re: A challenge exploding trees



Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


----- > >Have you ever gave a though why some trees "explode"
> >being hit by lightening and not seriously burned down
> >in  same time?
> >
> >regards,
> >Boris
> >
> >
>
> exploding trees and lightning most definately ...  millions of amps at
> 3+ million volts must = billion joules :)  all in 1 second or less  ouch
>  no wonder why they explode...  but milliamps at 2 million volts must =
> 10 mayybeee  20 J.  hot  but not that hot ...

Lightning is on the order of 10 kA... Around 100 kJ/meter dissipated in the
stroke itself and, at that kind of current, the voltage drop along the
channel is around 1000V/meter.  Still... dissipating 10's of kJ in a few
milliseconds is enough to strip the bark off a tree..

>  my question ..  is it the current or voltage in the rf form that did it
> ??   which brings us back to human contact...  it must be the "energy" (
> joules) that will do us in ...  whatya think??
>
Indeed.. joules are what kills....  although, given finite resistivity,
current, joules, pulse length, and voltage are all interrelated.