THE TRANSFORMER
1 mark · EasyWhat must be true for a transformer to work properly?
Show answer
Correct option: The current in the primary coil must be alternating (a.c.).
Common mistakes: Choosing 'secondary coil must be thicker'
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Correctly identifies that a.c. is required in the primary coil.
Worked solution
Transformers only work with a.c. because the magnetic field must be changing to induce a voltage in the secondary coil.