Electrostatic shielding
Using Gauss law, we
proved that the electric field inside the charged spherical shell is zero,
Further, we showed that the electric field inside both hollow and solid conductors is
zero. It is a very interesting property which has an important consequence.
Consider a cavity
inside the conductor as shown in Figure 1.48 (a). Whatever the charges at the
surfaces and whatever the electrical disturbances outside, the electric field
inside the cavity is zero. A sensitive electrical instrument which is to be
protected from external electrical disturbance is kept inside this cavity. This
is called electrostatic shielding.
Faraday cage is an
instrument used to demonstrate this effect. It is made up of metal bars
configured as shown in Figure1.48 (b). If an artificial lightning jolt is
created outside, the person inside is not affected.
During lightning
accompanied by a thunderstorm, it is always safer to sit inside a bus than in
open ground or under a tree. The metal body of the bus provides electrostatic
shielding, since the electric field inside is zero. During lightning, the
charges flow through the body of the conductor to the ground with no effect on
the person inside that bus.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.