What is electrostatics?
Author:Neeraj Kathuria
The branch of Physics, which deals with the study of charges at rest, the forces between the static charges, electric fields and potentials due to these charges is called Electrostatics or Static Electricity or even Frictional Electricity.
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What is electrostatics?[/caption]The term 'electrostatics' means the charges are either stationary or move very slowly with respect to each other. In this chapter, we will study the charges, their effects on each other and on the surrounding charges. The discussion and determination of quantities like electric force, electric potential and electric field etc. will be important definitely at various points due to different kinds of charge distribution because various important conclusions can be drawn from their values. Charge distribution on a given body is very important for the measurement of above quantities. For example, charge distribution can be on a line, on a surface and on a 3-D body. It may be uniform and non-uniform also. According to the shape of the body, charge on the body, we can have various values of electric force, potential and field at a given point. It is very important to say that the values of above quantities are responsible for various phenomena.
The two types of charges i.e. positive and negative were chosen arbitrarily by Benjamin Franklin. In conductors, the electrons are loosely bound so it is easy to remove electrons by using friction method, say by rubbing a given conducting rod with some rough material. On the other hand, insulators do not lose electrons easily, hence it is easier to put charge on them to make them charged.
The various phenomenon of electrostatics find industrial applications. Some of them are electrostatic paint spraying, powder coating, flyash collection in chimneys, photocopying etc.
Many more uses of the electrostatics are given as below.
The electric field inside a hollow conductor is zero so electrical circuit can be saved from any external charge or electric field by keeping it in a hollow conductor. It is worth mentioning that electrostatic force is mechanical force and it is used to give kinetic energy to charge particles. In an atom nucleus exerts centripetal force on electrons and they revolve in circular orbits around the nucleus. The atom is stable because of constancy of this force between nucleus and electrons and keeps the electrons at a constant distance from the centre of the nucleus. Sparking also occurs due to the electrostatic force between the opposite charges. The electrostatic force is also a reason for binding atoms together, molecules together to form solids and even the human being is an assembly of a nuclei and electrons held together by this force. So hopefully I think, now you understand how important is this electrostatic force, which is a very strong force and roughly 1036 times stronger than the gravitational force.
We can still elaborate more interesting applications of various phenomena of electrostatics. For example, command signal was sent from earth to the space craft voyager-2 by the help of oscillating motion of electrons.
A host of other phenomena and effects of electric field can be invented. We will not miss to highlight some of them, which have already been invented. For example, a shark can detect the weak electric field produced by the flatfish even if the latter is hiding itself by burrowing into the bottom soil. Similarly, the presence of human beings in water can be detected by shark because any scratch on the human body produces weak electric field.
We can even make the surrounding air conducting by a strong electric field and this is called electric break down or electrical discharge. Very interesting it is to observe the sparks in the air surrounding a charged metal cap. This is due to ionisation of the surroundings air. It happens only if the strength of the electric field is too large. In the beginning it has been rightly said that strength of the electric field matters so this example is very correct to explain the effect of electric field.
In industry also electric field finds beautiful uses. For example, when electric field exerts a force on charged ash in electrostatic precipitator then the ash is collected in the stack and not allowed to go out in the atmosphere and pollute it. This is how the electrostatic force can prevent the atmosphere from pollution. We can still go on telling more and more examples of the uses of electrostatics. The brilliant display in the sky stretching over few kilometers and delivering around 1000 amperes of current from clouds to the earth is a fine example of the strong electrostatic force between the oppositely charged particles. The overhead cloud system creates strong electric field near our heads and our hair strands extended along the field. Don't you understand that the above examples are based on the effects of charges at rest or in slow motion.
Capacitor is a wonderful device, which has been devised by the basic principle of electrostatics. It is used in almost all electronic equipments like oscillators, amplifiers, rectifiers, modulators, demodulators, calculators and definitely in computers. It is a device, which is used to help a patient suffering from ventricular fibrillation (a kind of heart attack). The heart muscles are given shocks by 20 A of current which transfers about 200 joules of energy in about 2 mile seconds. A special electronic circuit greatly increases the potential difference of capacitor there by increasing the electrical energy of the capacitor. This is really a wonderful application of electrostatics.
Thanks to the scientists who really did so well in initiating endless efforts for making this branch of physics so applicative and so important. To wind it up I would say this branch of physics is only the game which positive and negative charges play sitting on various bodies in different postures and spreading their influence in atmosphere, industries, research etc.
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About the Author
Neeraj Kathuria is an active article writer who is fond of sharing educational advices to help students to improve confidence and help them perform better at school and colleges. He has presented many articles on distance learning program for class xii, cbse test at home, test series for class neet and much more.
