Arrange the following in a sequence for the working of a transformer:
A. Magnetic flux changes through the primary coil.
B. An a.c. source is connected to the primary coil.
C. Magnetic flux changes through the secondary coil.
D. emf is induced in the secondary coil.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B, A, C, D
A transformer works by mutual induction: a changing current in the primary produces a changing flux, which the iron core carries to the secondary.
B — An a.c. source is connected to the primary coil.
A — Magnetic flux changes through the primary coil, because the alternating current in it keeps changing.
C — Magnetic flux changes through the secondary coil, as the core links the same changing flux to it.
D — emf is induced in the secondary coil, by Faraday’s law.
So the order is B, A, C, D.
NCERT (2026-27):
Transformers – “… When an alternating voltage is applied to the primary, the resulting current produces an alternating magnetic flux which links the secondary and induces an emf in it.”