You\'ve o en often heard that you shouldn\'t stand near a tree during a lightnin

Question

You've o en often heard that you shouldn't stand near a tree during a lightning storm. It's not just because trees axe more likely to attract a lightning strike, but also because of side flashes-bolts that jump from the tree to a nearby conducting body (like your body.). As the electrical current of the lightning runs down the side of the tree it may hit a patch of greater resistivity (due to dry tree bark) and a portion o e current may divert through the air and pass down to the ground via your body, which has negligible resistivity compared to the air or the dry' tree bark. To get a sense of how dramatic the effect might be, recall that about 10 C of charge may be delivered to the ground by a lightning strike, and that the strike itself may be over in the span of even 2 milliseconds. You want to model the situation by thinking of the path through the tree and the path via the air and then through a person t body' as different branches of a circuit that ultimately connects to the ground (literally!). Yon start by assuming that the resistivity' of the dry tree bark and the air are comparable and that the area through which the current travels is about the same along both branches. You want to know how much of the current would be diverted through the person (starting at their head) if they are about 1.5 meters tall and stand about a half-a-meter away from the tree.

Explanation / Answer

current is amount of charge per unit time.

here current= charge/time= 10 / ( 2x 10^-3)= 5000 A

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