Question

In a transformer, in which the losses may be neglected, the ratio of the primary voltage to secondary voltage is found to be $4:1$. The ratio of the primary to secondary turns and the ratio of the primary current to secondary current are respectively in the ratio of :

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

Answer 1

The correct option is A 4 : 1 & 1 : 4

$\frac{V_p}{V_s}=4$

as we know, $V\propto \frac{1}{i}$, and $i\propto \frac{1}{no.ofturns}$

Ratio of primary current to secondary current

$\frac{i_p}{i_s}=\frac{V_s}{V_p}=\frac{1}{4}$

$\frac{i_p}{i_s}=\frac{n_s}{n_p}=\frac{V_s}{V_p}$

$\frac{n_s}{n_p}=\frac{1}{4}$

Ratio of primary to secondary turns

$\frac{n_p}{n_s}=\frac{4}{1}$