03 Feb How is electricity conducted through wires?
In today’s physics tuition we will cover an interesting topic – how is electricity getting conducted through wires? In today’s physics tuition, we will find answers to this question. Electricity is supplied to our homes, schools, factories and stores through copper or aluminium wires from the powerful generators present in different types of power stations. The electricity is generated in different types of power stations where they burn coal or oil, use nuclear reactions or energy of falling water, to produce energy to run the generators. Electric power stations are generally situated in remote areas where it is cheaper to produce electric power. This power is then transmitted to the different cities and places where it is required. Electricity is transmitted through transmission lines which consist of two parallel wires for carrying current from the power station.
To avoid the loss of power, the output voltage from the generator is first stepped up to a high voltage by a step-up transformer. After being received at the city power station, it is reduced to low voltage, before it reaches our homes or factories. Now the question arises, how electricity is conducted through wires.
We know that all substances are made up of atoms. Materials which allow the passage of electricity are called conductors. Metals such as copper, aluminium, silver and gold are good conductors of electricity. The atoms of these metals have loosely-bonded electrons. These electrons are free to move within the metal. These are called free electrons and are responsible for the current to get conducted. The more the number of free electrons in the metal, the better conductor of electricity it is.
When electric battery or any other electrical source is connected across the ends of the metal wire, the negatively charged free electrons move away from the end connected to the negative terminals and flow towards the positive terminal. This flow of electrons is the electric current. Hence the drifting electrons cause the electricity to flow. The greater the number of free electrons in a metal, the easier it is for electricity to move through it.
Some materials are poor conductors of electricity because they have fewer number of free electrons. Poor conductors resist the flow of electricity. The resistance of a wire depends upon its length and area of a cross-section.
Some substances do not allow the electricity to flow through them. Such substances are called insulators. These substances contain tightly-bonded electrons that cannot move away from atoms. Hence, they do not conduct electricity. Glass, mica and rubber are common insulators. Wood and plastic are also used as insulators. Some substances, like silicon and germanium are neither good conductor nor insulators. They are called semi-conductors.
We hope you enjoyed this lesson from physics tuition. We will be back with more such interesting findings in our next physics tuition.
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