Question

A transformer is an electrical device that works on the principle of self-induction.

A. True
B. False

Answer 1

A transformer is made up of 2 coils. One coil is given with the input voltage. The magnetic flux gets generated in the core when this voltage produces a current in the coil. The other coil produces a voltage when the magnetic flux generates links with this coil.

Formula used:
$E=-\dfrac{d\phi }{dt}$

Complete step by step answer:
Faradays’ law of electromagnetic induction states that the emf gets generated in the coil which is kept in the changing magnetic flux.
Mathematically, the expression for Faradays’ law of electromagnetic induction can be given as follows.
$E=-\dfrac{d\phi }{dt}$
Where a negative sign indicates the opposite direction of the flux generated.
A transformer is an electrical device used to vary the input voltage. The construction of a transformer:- it consists of coils, named as the primary coil and the secondary coil, both are wound on the same core.
The voltage is given as the input to the coil named the primary coil. This produces a current in the other coil named the secondary coil. Even, as a result, the magnetic flux gets generated throughout the core. When this magnetic flux gets linked to the secondary coil, as a result, the voltage gets produced in the secondary coil.
Thus, the transformer works on the principle of mutual induction and not on the principle of self-induction.

As the transformer works on the principle of mutual induction, thus, the option (B) is correct.

Note:
We need to understand the difference between self-induction and mutual induction. In the case of mutual induction, the magnetic flux generated by one coil when current passes through it, and this magnetic flux when links with the other coil, the voltage gets produced. Whereas, in the case of self-induction, the magnetic flux generated by the current flowing the coil links with itself and produces the voltage.