Question 7

  Explain how a bolt of lightning can produce a current in the circuit of an electrical appliance, even when the lightning does not directly strike the appliance.

SOLUTION: Electromagnetic induction. A lightning bolt going by would be a sudden change in current (from none to really big) and hence a sudden change in magnetic field around the lightning bolt. If an electrical appliance has coils, the changing magnetic field induced by the lightning bolt would cause a changing magnetic flux through the coils in an electrical appliance. This changing magnetic flux would induce, by Faraday's Law, an emf in the coils. This emf would produce a current in the appliance.