Question

A transformer works on the principle of ___________________

1. Self-Induction
2. Electrical Inertia
3. Magnetic effect of electric current.
4. Mutual Induction.

Answer 1

In our homes whenever the voltages are low we use to push a button in a box made of metal. Similarly whenever the voltages are very high we use to push down the button on the same metallic box. That metallic box is known as a transformer.

Complete step by step answer:
A transformer is a machine which is designed to convert AC (Alternating Current) from one voltage to another voltage. It can act as a “Step up” or “Step down” voltage transformer i.e. it can up the voltage or down the voltage as per one's requirement. The moving parts in a transformer are none; it is also known as a static solid device. Since moving parts causes wear and tear, the transformer having no moving parts grants a long shelf life. The transformer consists of two coils which are insulated and is wound on a laminated core made of steel. The lamination of the steel core happens because there can be electrical and magnetic interference in the core.

Transformer works on faraday’s law of Electromagnetic induction, which is given as:
$\varepsilon = - N \dfrac{\Delta \phi}{\Delta t}$, where $\varepsilon$ = Electromotive force, $\Delta \phi$ = Magnetic flux, $\Delta t$ = Change in time and N = Number of turns in the wire.
It basically states that the rate of change of magnetic flux times the number of turns generates a force known as electromotive force.
Self-Induction means that an electromotive force is induced in the same circuit in which the current varies. When this same electromotive force is induced in the adjacent coil keeping the magnetic field the same for both the coils, the emf is said to be magnetically induced or it can be stated as Mutual Inductance. In the transformer two or more than two coils are magnetically linked together by a common flux which is magnetic in nature they possess properties of mutual inductance.

Final Answer: Option “4” is correct. A transformer works on the principle of mutual inductance.

Note: There are two types of transformer one is a three phase transformer and another is a one phase transformer. In a single phase transformer the transformer consists of one conductor and one neutral wire. Whereas three phase supply has three conductors and one neutral wire. Single phase transformers can be used in place of three phase transformers.