Question

The primary winding of a transformer has 100 turns and its secondary winding has 200 turns. The primary is connected to an A.C. supply of 120 V and the current flowing in it is 10 A. The voltage and the current in the secondary are

• A. 240 V, 5 A
• B. 240 V, 10 A
• C. 60 V, 20 A
• D. 120 V, 20 A

Answer 1

Answer: (A)

240 V, 5 A

Answer 2

We know that, $\frac{ N _{ s }}{ N _{ p }}=\frac{ V _{ s }}{ V _{ p }}$ $\Rightarrow \frac{200}{100}=\frac{ V _{ s }}{120}$ $\Rightarrow V _{ s }=\frac{200 \times 120}{100}=240 V$ Also, $\frac{ V _{ s }}{ V _{ p }}=\frac{ i _{ p }}{ i _{ s }}$ $\Rightarrow \frac{240}{120}=\frac{10}{ i _{ s }}$ $i _{ s }=\frac{10 \times 120}{240}=5 A$ Thus $V _{ s }=240 V , \quad i _{ s }=5 A$