What will be the primary voltage of a transformer if the secondary voltage is 60 V and there are 40 loops on the primary coil and 120 loops on the secondary coil?

20 V

Explanation:

We can solve this problem by applying the transformer formula:

V (out) / V (in) = Ns / Np

Where V (out) = voltage at the secondary coil

V (in) = voltage at the primary coil

Ns = number of loops in the secondary coil

Np = number of loops in the primary coil

From the question:

V (out) = 60 V

Ns = 120

Np = 40

We need to find V (in)

V (in) = V (out) * Np / Ns

V (in) = (60 * 40) / 120

V (in) = 20 V

The voltage in the primary coil (primary voltage) is 20 V