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Suppose a lightning strikes and there is an iron rod and a coconut tree. How does the electricity know that rod is the least resistant path before hand.

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  • $\begingroup$ Your question assumes that the iron rod will be struck and not the tree. The most resistive path is through the air and what matters more is the amount of air between the target and the charge. Whichever is closer to the bulk of the charge is likely to be the one struck. $\endgroup$ – Brandon Enright Apr 11 '13 at 17:48
  • $\begingroup$ Assuming this happens in vaccum. The question is about fundamental nature of electricity.The rod and tree scenario in the question is just an example. $\endgroup$ – Sreekanth Karumanaghat Apr 11 '13 at 17:53
  • $\begingroup$ The breakdown voltage of a vacuum is huge. en.wikipedia.org/wiki/Breakdown_voltage The principle is the same though. Whichever object (the rod or the tree) has the greater charge potential over the distance will be struck. $\endgroup$ – Brandon Enright Apr 11 '13 at 18:00
  • $\begingroup$ Also I don't think lightning will work in the traditional way in a vacuum. An ionization path won't get created so the charge that moves between the two regions won't move rapidly all along the same path. $\endgroup$ – Brandon Enright Apr 11 '13 at 18:02
  • $\begingroup$ I think this is what I intended to ask... please see my comment below an answer.. physics.stackexchange.com/q/5670 $\endgroup$ – Sreekanth Karumanaghat Apr 11 '13 at 18:05