A transformer has a primary voltage of 115 V and a secondary voltage of 24 V. If the number of turns in the primary is 345, how many turns are in the secondary? A. 8 B. 690 C. 72 D. 1,653

C. 72

Explanation:

Transformer: A transformer is an electromagnetic device that uses the property of mutual inductance to change the voltage of alternating supply.

In a ideal transformer,

Vs/Vp = Ns/Np ... Equation 1

Where Vp = primary voltage, Vs = secondary voltage, Ns = Secondary turn, Np = primary turn.

Making Ns the subject of the equation,

Ns = (Vs/Vp) Np ... Equation 2

Given: Vs = 24 V, Vp = 115 V, Np = 345.

Substitute into equation 2

Ns = (24/115) 345

Ns = 72 turns.

Thus the number of turns in the secondary = 72 turns.

The right option is C. 72