Shielding from Electric Fields with Conductor

Shielding from Electric fields with conductor

Electrical Conductors are used all over the world for one main purpose, which is to shield from Electric Fields. Electrical conductors can be found in various electronic appliances such as clocks, blenders, vacuum cleaners, stereos, monitors, televisions and many more, which all produce electric field; an electric field is a field extending outwards in all directions from charged particles, such as protons and electrons. Furthermore, an electrical conductor is defined as any material that allows the flow of electrical current. Examples of some conductors are gold, silver and copper.

As charged particles are placed on an uncharged conductor, the charged particles redistribute themselves along the surface of a conductor until they reach a point that no net force is experienced. This point is referred to as electrostatic equilibrium. Some of the properties which a conductor possesses at electrostatic equilibrium are; that the electric field equals to zero everywhere inside the conductor and the electric field just outside the charged conductor is perpendicular to the conductor’s surface. To support the existence of electrostatic equilibrium, a famous English chemist and physicist, Michael Faraday in the early nineteenth Century placed himself and an electroscope inside a tin foil-covered booth, known as “Faraday cage”, to demonstrate the effect of enclosed cavities. Faraday had the booth, which is an enclosure formed by conducting material, charged by means of an electrostatic generator; an electrical device that creates a high voltage by building up a charge of static electricity. Faraday noticed that even though sparks were flying outside, inside he detected no electric field. In depth, a “Faraday cage” is known as an ideal hollow conductor. In Michael Faraday’s experiment, forces produced by outer electric fields on the charge carriers within the conductor generated a current that rearranged the charges. As the charges finished rearranging, the applied field inside canceled, causing the current to stop. This static (stationary) equilibrium caused the electric field inside the “Faraday cage” to equal zero. This demonstration from Michael Faraday is a valid example, where conductor is used to shield from electric fields. Furthermore, one property of conductors at electrostatic equilibrium which helps charges stay in equilibrium is that the electric field is always perpendicular to the surface of the conductor. Due to this property the parallel component of the electric field equals to zero causing the charges not to move. This is one of the most important properties which make an electrical conductor, excellent shields against electric fields.

(Nelson Physics 12 p. 346)

In our atmosphere, stray electric fields are frequently formed.