There is an alternating current of 12 A in the primary coil of a transformer.
There is an alternating current of 3 A in the secondary coil of the transformer.
The transformer is 100% efficient.
The size of the potential difference (voltage) across the secondary coil is:
four times the size of the voltage across the primary coil
one-quarter the size of the voltage across the primary coil
four times the size of the current in the primary coil
one-quarter the size of the current in the primary coil
28 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid. Each one has a worked solution and a mark scheme showing where the marks go.