UPSC » UPSC CSE Study Materials » Physics » Brief Notes On Electrostatic Shielding

Brief Notes On Electrostatic Shielding

When a Faraday cage is utilised to block the effects of an electric field, the phenomenon known as electric shielding occurs. The cage blocks the impact of external fields on the inside contents.

Electric shielding is a technique for shielding a specific area of space, or any sensitive building or device, from the external field of an electric charge. For instance, high-voltage measurement equipment like CRO is kept inside a Faraday cage, a hollow conductor or cage. The reality of reserving such an instrument within the conductor, as per the practical demonstration of electrostatic shielding, is that when there is no charge within it, there is no electric charge within a closed conductor. So let’s discuss all about electrostatic shielding in detail so that you will get all the necessary information. 

Electrostatic Shielding Applications

Electrostatic shielding protects an area from threats, including an external electric field.

Consider the following electrostatic shielding applications:

  • Car Electrostatic Shielding: Sitting inside a car is safe throughout a lightning storm because the car’s metallic body functions as an electrical shield

  • Electrostatic: Shielding is used during audio cables to protect them from external interference, including an electric field generated by air electricity and electric sparks.

  • Electrocution: Electric shock and electrocution can kill linemen. Thus they wear Faraday cage suits to protect themselves.

  • Elevators in buildings act as an electrostatic barrier, preventing cell phones, radio, or audio broadcasts from being picked up.

  • To provide electric shielding to the signals transmitted by the central conductor, the coaxial cables in the outside conductor were linked to the ground.

Faraday Cage

The Faraday cage is a container that shields conductive objects from external electric fields. A Faraday shield is another name for it.

Michael Faraday invented the Faraday cage in the year 1800. Whenever he charged the metal cage, which acts as an electrical conductor, he observed that the charges only appeared on the surface and had no effect on the interiors. He lined a chamber in metal foil on a bigger scale, allowing high-voltage discharges from an electrostatic generator. He used an electroscope, a device that detects electric charges, to confirm his theory that the metal foil’s outside surface was conducting electricity. In contrast, the rest of the room was devoid of them.

Faraday Cage Working

Faraday cages were made of fine metal mesh and chain-like fences that come in various sizes and forms, giving them a cage-like appearance. It may contain electrostatic charges or electromagnetic fields within the cage, which are distributed outside the material on which it is used. The charges on the outside were spread to cancel with the charges on the inside.

The Behaviour of Conductors in Electric Field

Electrons in conductors are still not securely linked to their atoms. Within the conductor, these are free to travel around. In the absence of an applied electric field, there is no net flow of electrons (charges) from one side of the conductor to the other. It is claimed that the conductor is in electrostatic equilibrium. Whenever an external electric field E is applied to a conductor, the free electrons are propelled in the opposite direction of the electric field. As a result, electrons accumulate on the conductor’s surface ABCD. The loss of electrons causes the FGHK surface to be positively charged. These charges (-ve on the ABCD surface and +ve on the FGHK surface) generate their fields in the opposite direction of E.

 

In Physics, What is Electrostatic Shielding Definition?

We’ll look at how sensitive electrical instruments are or why they need to be shielded. The device that needs to be protected from an external electric field is placed inside the conducting box (copper), and also the Van de Graff generator is positioned near it.

The electric field created by the generator attracts electrons from one side of the box to the other, resulting in a net positive charge on the opposite side of the box. The charge dispersion also produces an electric field. As per Gauss law, the net electric field within the conductor is zero at every point. So, does the conductor shield the instrument from just an electric field from the outside?

It certainly does. So when an electric field acts on a Faraday cage (a copper box), the charges within the cage reorganise themselves to counterbalance the field directly, the shield (protection) of the cage’s internal from the exterior electric field is created.

Conclusion

Electric shielding protects components and assemblies from external electrostatic fields, which can cause damage and failure. The needed shielding level is indicated by the electric field level that causes the failure. Electrostatic effects induced within one volume by an external electrostatic field have been avoided since the dawn of electricity by utilising a highly conductive enclosure that acts as an electrostatic shield. I hope now you understand all about Electric shielding in detail for better understanding you must go through the topic thoroughly. So that it will clear all your doubts and you’ll get all the necessary information.

faq

Frequently asked questions

Get answers to the most common queries related to the NEET UG Examination Preparation.

What is the electric shielding definition?

Ans. Even if the conductor is charged and an external field induces charges on even a neutral conductor, all charges...Read full

For instance, what is electrostatic shielding?

Ans. Electrostatic shielding is the process of rendering a zone free of any electric fields. Applications: It is saf...Read full

What role does electrostatic shielding play?

Ans. Electrostatic Shielding in Practice ...Read full

What causes the electrostatic field to be zero?

Ans. Although charges were present on the surface of a conductor, the electros...Read full