Gauss’ Law has an important practical application. Imagine a solid conducting object which may be in a strong electric field. If all excess charge is on the surface of the conductor and if there is no electric field inside the conductor, then it should be possible to remove any conducting material from the interior without changing the location of the charges or the electric field inside. This will leave a hollow metallic shell which has no electric field inside it. There is no electric field inside even if there is a strong field outside: the conducting shell acts as a “shield” against electric fields. Furthermore, the hollow shell can have holes in it or even be made of a wire mesh and still retain its shielding property. Such a space surrounded by a conductor is called a “Faraday cage”. Materials : • A metal cup • A hard plastic rod and fur • A metallic ball suspended by a thread Now try the experiment without touching the can with your hand or any other electrical conductor. Was your prediction verified or not?

Gauss’ Law has an important practical application. Imagine a solid conducting object which may be in a strong electric field. If all excess charge is on the surface of the conductor and if there is no electric field inside the conductor, then it should be possible to remove any conducting material from the interior without changing the location of the charges or the electric field inside. This will leave a hollow metallic shell which has no electric field inside it. There is no electric field inside even if there is a strong field outside: the conducting shell acts as a “shield” against electric fields. Furthermore, the hollow shell can have holes in it or even be made of a wire mesh and still retain its shielding property. Such a space surrounded by a conductor is called a “Faraday cage”. Materials : • A metal cup • A hard plastic rod and fur • A metallic ball suspended by a thread Now try the experiment without touching the can with your hand or any other electrical conductor. Was your prediction verified or not?