Question

In a transformer the number of turns in the primary coil is 200 and secondary coil is 600. The ratio between the electric current in the primary and secondary respectively is

• A. 1 : 4
• B. 4 : 1
• C. 1 : 3
• D. 3 : 1

Answer 1

The correct option is D 3 : 1

In a transformer, we know that
$\frac{V_2}{V_1}=\frac{N_2}{N_1}$
where $V_1$ and $V_2$ are voltage across primary and secondary coils respectively and $N_1$ and $N_2$ are respective number of turns.

Also, the transformer doesn't add or take away energy, so the power in

the primary and secondary is equal:

$V_1{I}_1=V_2{I}_2$
Therefore, $\frac{I_1}{I_2}=\frac{N_2}{N_1}$
$\frac{I_1}{I_2}=\frac{600}{200}=\frac{3}{1}$
Hence, desired ratio is 3:1. (D)