Arrange the following steps in correct order of electromagnetic induction in a transformer.
A. The primary coil produces a magnetic field that induces an emf in secondary coil.
B. An ac current flows through the primary coil.
C. The direction of induced current is determined by Lenz’s law.
D. The induced emf in secondary coil produces an electric current.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B, A, D, C
A transformer works by mutual induction: a changing current in the primary produces a changing magnetic flux, which links the secondary and induces an emf in it.
B. An ac current flows through the primary coil. — this is the cause; the current must change with time.
A. The primary coil produces a magnetic field that induces an emf in secondary coil. — the changing flux through the common core links the secondary (Faraday’s law).
D. The induced emf in secondary coil produces an electric current. — once a load is connected, the induced emf drives a current.
C. The direction of induced current is determined by Lenz’s law. — this comes last, since it describes the current that has been set up: it flows so as to oppose the change in flux (Lenz’s law).
Correct order: B, A, D, C.