Faraday Cage
A Faraday cage or Faraday shield is an enclosure made of a conducting material. The fields within a conductor cancel out with any external fields, so the electric field within the enclosure is zero.
These Faraday cages act as big hollow conductors. You can put things to shield them from electrical fields. Any electrical shocks the cage receives, pass harmlessly around the outside of the cage.
A point charge of 2C is placed at centre of Faraday cage in the shape of cube with surface of 9 cm edge. The number of electric field lines passing through the cube normally will be
Options:
(a) `1.9 xx 10^5 N-m^2'/'C`, entering the surface
(b) `1.9 xx 10^5 N-m^2'/'C`, leaving the surface
(c) `2.01 xx 10^5 N-m^2'/'C`, leaving the surface
(d) `2.01 xx 10^5 N-m^2'/'C`, entering the surface