Question

What is the principle of a transformer?

Hint:

Transformers cannot work with DC supply as there is no changing flux.

Answer 1

Step 1: Transformer basics.
A transformer has two coils (primary and secondary) wound on a core.
Step 2: Principle.
When AC flows through the primary, a changing magnetic flux is produced in the core. By Faraday’s law, this induces an emf in the secondary coil.
Step 3: Equation.
\[ \frac{V_s}{V_p} = \frac{N_s}{N_p} \] where $V_s, V_p$ are secondary and primary voltages; $N_s, N_p$ are turns in the secondary and primary coils.
Step 4: Conclusion.
Thus, a transformer works on the principle of mutual induction between two coils.