The electric field is a property of charge at rest. The field has a nature whether it is positive or negative, but if it is positive it will repel all positive charges and vice versa. The field may be strong or weak depending on the strength of the charge. However, it can be useful if we want to prevent a system from the external impact of any other field. The electric field of charge at the surface will protect the system inside the surface. We have lots of simple examples of electrostatic shielding like chains hanging on the back side of trucks, conductor wire on a high building to prevent lighting, etc.
Electrostatics is a part of physics in which we study the properties of charge at rest. Now, what is a charge? The charge is a property of any elementary particle because if that particle experiences or exerts an electric force on another particle. The standard unit to measure the charge is Coulomb and it is a scalar quantity. In this branch, we focus on charge at rest or we can say charge in slow-motion. As the charge is at rest or moving slowly, it shows the only electric effect and has no magnetic field.
As we know shielding means preventing something from external attacks. To prevent an object we use a shield and it can be of any metal, non-metal, or any other virtual shield.
Here, we are studying electrostatic shielding, which is a process or method to prevent any object, location, or sensitive equipment from an external electric or magnetic field. In this method of prevention, we use the principle that states that every conductor has an electric field on the surface, not inside the conductor. So, we design a system so that it will behave like a conductor and the object we want to prevent will remain inside the system so it will have no impact on the external electric field.
We can see the practical example of electrostatic shielding on the lorry trucks, every truck tanker has a hanging chain on the back of the truck. As the truck moves tanker will be charged due to air friction and store a huge amount of charge that will be harmful. This chain act as shielding to prevent the extra charge from storing on the surface of the tanker by sending the extra charge to the earth.
Fig: 1 Electrostatic shielding
User:しまでん, Electrostatic shielding, CC BY-SA 3.0
Faraday cage, you can judge it by name that it will be same like a cage, by property or shape. It is a cage-like structure incented by Michael Faraday in 1800.
Michael Faraday introduced the theory first that when we create a cage of metal or any conducting material then the whole cage will act like a complete conductor. Then it will act like a conductor then there will be no charge inside the conductor and the complete charge will be concentrated on the surface.
To verify this theory on large scale, he made an experiment in his room where he covered the room with metal sheets like aluminum foil. Then he set up a source of high voltage current. When he applied that high voltage to the metal foil, he found that the complete charge was concentrated on the foil and zero charges were detected inside the room by the electron microscope.
Fig: 2 Faraday cage
Architectual Elements - www.Archele.com , Archictetural Elements Faraday Cage, CC BY-SA 4.0
Faraday cage is the best instrument for shielding against high voltage electric pulses and electric fields. Some of the important applications of the faraday cage are the following:
Anti-Static bags: Most companies use the faraday cage principle for developing anti-static bags for delivering goods and gadgets. We know some digital gadgets like hard-drive, which are based on electric and magnetic fields can be affected by external fields. So, these devices are delivered by using such shielding.
We can also use the faraday cage principle for making the electrostatically isolated shelter or warehouse. These shelters are used for parking some expensive digital devices like super-computer.
MRI: For MRI testing we use an isolated chamber to prevent inter-mixing of external electric signals in original data. As MRI is a magnetic field-based technology so it can be affected by external electric fields.
Microwave Ovens: Microwave ovens are also based on the Faraday cage to prevent the extraction of internal electromagnetic radiation from the outer region. This makes the oven more efficient.
Electrically Neutral Environment: We have to perform various experiments for development in many fields like chemistry, biology, physics, etc. Some experiments are operated on a sensitive instrument so to get a higher rate of accuracy we have to set up an isolated environment that can be possible by the use of the Faraday Cage.
In the modern era of digitalization, we can say that electrostatic shielding is also important as devices are important. Let's have a look at the applications of electrostatic shielding.
We can use this principle of electrostatic shielding for the wires which are carrying the signals like audio signals, messaging signals, etc.
To prevent buildings from the lightning shock we use a conducting wire that provides electrostatic shielding.
Electrostatic shielding is also used by car manufacturers to prevent passengers from shocks.
The Faraday cage is also an application of electrostatic shielding.
To work with high voltage, workers wear clothes that are manufactured by any conducting material to prevent external effects. This is known as electrocution.
Electrostatic shielding is quite important in this digital era to provide a safe zone for our digital gadgets. This innovation is a measurable step in the field of the safe use of electricity. This technology is very important to prevent objects from heavy electromagnetic pulses like a power surge.
Q1. What do you mean by Electrostatic Equilibrium?
Ans. It is a situation or condition in which a charged conductor gives rise to a state when extra charges start moving away as they overcome repulsive force.
Q2. why do we earth the cage?
Ans. when we use a faraday cage for electrostatic shielding then the surface of the cage will acquire a huge charge. The extra charge is sent to earth to prevent any mishappening due to excess charge.
Q3. What is the magnitude of charge for one electron?
Ans. The magnitude of charge at an electron is $\mathrm{1.6\:\times\:10^{-19}\:coulomb}$.
Q4. How many kinds of charges are present in the universe?
Ans. There is two kinds of charges; positive and negative.
Q5. What do you mean by Electrostatic Induction?
Ans. Electrostatic induction is a process or phenomenon in which we charge a body for a short duration or temporarily where we can see that opposite charges appear on the nearby particle and the same charge at the farther particle, this phenomenon is natural and known as Electrostatic Induction.
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