What is Electricity?
In ancient times, man had no idea of electrical energy. They took the flash of lightning during a thunder storm to be a signal for an impending destruction from the heavenly Gods. With the passage of time, science in its own way explained the mystery of this great energy called electricity.
Today, we cannot imagine the normal life without electricity. Commonly we know it as a form of energy, that powers almost all machines or mechanical devices — trains, radios, television sets, freezers and so on. Electricity is a phenomenon involving electrical charges and their effects, when at rest as well as when in motion.
Electricity that we use flows through wires as electric current. In a nutshell, when an electric current flows through a conductor of finite resistance, the heat energy is continuously generated at the expense of electrical energy. The particles of a matter may be positive, negative or neutral. We know that electricity has its two important particles — protons and electrons. Electron is negatively charged while
proton is charged positively to an equal extent. The object containing an equal number of protons and electrons is electrically neutral. For example, anode is a positive electrode while cathode is a negative one. Bulk of the electricity we use is produced in power stations. In the generator of a power station, coils of wire are made to rotate between powerful magnets in order to rotate electric current through the coils. Electricity travels through substances like copper, aluminium and iron. These are called conductors. However, electricity cannot pass through some materials like rubber and glass and these are called insulators.
Electricity which flows in one direction and then in the opposite is called Alternate Current (A.C.). Each movement of A.C., back and forth, happens very quickly – about 50 times a second. The electricity that flows in our houses is mostly A.C. Steady flowing current in one direction only is known as Direct Current (D.C.). For instance, battery current is D.C.
Soon after the invention of electric cell by Alessandro Volta, people came to know that heat, light, chemical reactions and magnetic effects could be produced from electricity.
As early as 600 B.C. Greeks discovered electricity by rubbing Amber with cloth which enabled it to attract small pieces of papers. In fact, the word electric originated from the Greek word Electron. Based on the theory of “Electro-Magnetic Induction” of Michael Faraday in 1831, first successful generator or Dynamo was made in Germany in 1867. USA produced; electricity by running turbines with the help of falling water in 1858.
Subsequently hydel and thermal power stations came into existence all over the world. During the 20th century many nuclear power stations were established to meet the growing demand of electricity.