The top of the atmosphere is at about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about 100 Vm–1. Why then do we not get an electric shock as we step out of our house into the open? (Assume the house to be a steel cage so there is no field inside!)
Dry atmosphere is not a conductor. Only when top of the atmosphere increases to a very large value and there is moisture in the air, the lightning strikes the ground. Since, 400 kV is not very high voltage so, it will not strive the ground. Since, our body and the surface of earth, both are conducting, therefore our body and the ground form an equipotential surface. As we step out in to the open from our house, the original equipotential surfaces of open air change, keeping our body and the ground at the same potential. That is why we do not get an electric shock.
