Transformers and Induced Current

Steps:

• In a transformer, alternating current in the primary coil creates a changing magnetic field in the iron core.
• This changing magnetic field induces an electromotive force (EMF) in the secondary coil via Faraday's law.
• The induced EMF causes an alternating current to flow in the secondary coil if the circuit is closed.
• The magnetic field is shared by both coils through the core, so it's present equally for both.

Why C is correct:

• Faraday's law states that a changing magnetic field induces EMF in any coil linked to it, so the field in the core affects the secondary coil just as it does the primary.

Why the others are wrong:

• A: Both coils have AC; DC in secondary would require rectification, not standard transformer operation.
• B: Current magnitude depends on turns ratio; secondary current is larger only in step-down transformers, not always.
• D: AC is induced in secondary, but it's equally true for primary, not distinctive to secondary.

Final answer: C