Physics · Potential difference, equipotential surfaces, electrical potential energy of a system of two point charges and of electric dipole in an electrostatic field

The top of the atmosphere is about 400 kV with respect to the surface of the ear

The top of the atmosphere is 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 \( 100 V m^{-1} \) Still, we do not get an electric shock as we step out of our house into the open house, because (assume the house to be a steel cage so that there is no field inside)

  • A. There is a potential difference between our body and the ground
  • B. \( 100 \mathrm{Vm}^{-1} \) is not a high electric field so that we do not feel the shock
  • C. our body and the ground forms an equipotential surface
  • D. The dry atmosphere is not a conductor

Step-by-step solution

When stepping out of a steel cage (Faraday cage), we are in contact with the ground, making our body part of the ground's equipotential surface. Since there is no potential difference across our body, no current flows, preventing electric shock despite the atmospheric electric field.
Practise more in this unitView MCQsSign up for full question bank