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. 1,653

B. 690

C. 72

D. 8

There are numerous information's of immense importance already given in the question.

Primary voltage of the transformer (V1) = 115 V

Secondary voltage of the transformer (V2) = 24 V

Number of turns in the primary (T1) = 345

Let us assume the number of turns in the secondary = T2

Then

(V1/V2) = (T1/T2)

(115/24) = 345/T2

115T2 = 345 * 24

115 T2 = 8280

T2 = 8280/115

= 72

So the correct option among all the options given in the question is option "C".