Question

In a step up transformer, the ratio of turns of primary to secondary is 1:10 and the primary voltage is 230 V. If the load current is 2 A, then the current in the primary is

• A. 20 A
• B. 10 A
• C. 2 A
• D. 1 A

Answer 1

The correct option is A

20 A

Consider the Voltage in Primary Coil be V1 and Voltage in Secondary Coilbe V2

Also, Number of turns in Primary Coil be N1 and Number of turns in Secondary Coil be N2.

So, the relation between these terms is :-

$\frac{V1}{N1}=\frac{V2}{N2}$

$\frac{N1}{N2}=\frac{1}{10};\frac{V1}{V2}=\frac{N1}{N2}$
$\frac{230}{V2}=\frac{1}{10}$
$V2=2300$

We have known that,
$V1I1=V2I2$
$I1=\frac{V2I2}{V1}=\frac{2300\times 2}{230}=20A$