Electricity

Let Us Learn About Electricity.

Electricity is one of the most important sources of energy. Lights, fans, motors, radios and television are some common appliances which work on electricity. In general usage, the word "electricity" is adequate to refer to a number of physical effects. In scientific usage, however, the term is vague, and these related, but distinct, concepts are better identified by more precise terms.

It can also define as, Electricity is a form of energy produced by the movement of electrons. Electricity is electrical power or an electric current. This form of energy can be sent through wires in a flow of tiny particles. It is used to produce light and heat and to run motors.

Now Let Us learn about Electric Charges

The word'electric' is derived from the Greek word 'elektron' meaning amber. The existences of charges were known when charged particles were produced by rubbing (due to friction) of suitable materials. These facts are demonstrated by simple experiments.

a) uspend a glass rod rubbed with silk. Bring another glass rod rubbed with silk nearer to the suspended rod. It is observed that, the suspended rod will swing away, showing repulsion.

b)Similarly, suspend a plastic rod rubbed with fur and bring another plastic rod rubbed with fur closer to it, we observe that the rods repel.

c)Again, if we suspend a glass rod rubbed with silk and bring a plastic rod rubbed with fur nearer to the glass rod, we observe that the rods attract.

From the above, we find that glass rod rubbed with silk acquire 'something' different from that of plastic rubbed with fur. That 'something' is called 'charge'.

To know about the electric charges we must know the structure of atom. It was discovered in 1911, by Rutherford performed by Hans Geiger and Earnest Marsden, under the direction of Rutherford that an atom is made up from the protons and neutrons in the nucleus, with a very small contribution from the or biting electrons

An atom consists of nucleus centrallyplaced with protons consisting positive charge. They seem to be surrounded by a kind of invisible force field.

This is called a a electrostatic field

The neutral particles are neutrons.

The electrons are the negative charged that revolves around the nucleus. This negatively charged electrostatic field is exactly the same strength as the electrostatic field in protons.

The negative charge of an electron is the same as the positive electrical charge of the much larger in size proton. This way the atom stays electrically neutral. The value of one charge is 1.6×10⁻¹⁹ coulombs (+ for protons and – for electrons).

In Physics we usually call the charge as electric charge, electrostatic charge, electrical charge or simply charge. We denote it by q. +q means protons and –q means electrons.

In a neutral atom the number of protons and number of electrons are same hence it does not carry any charge. But when the number or protons and number or electrons vary then atom acquires charge. If there are fewer electrons than protons, the atom has a positive charge. The amount of charge carried by an atom is always a multiple of the elementary charges, the elementary charge is e (e = ± .6×10⁻¹⁹ coulombs). When an atom losses electrons than it acquires positive charge and when it gains electrons it acquires negative charge. Hence, the net charge on an atom is q = ne, where n is number or electrons lost or gained.