Question

In a transformer the number of primary turns is four times that of the secondary turns. Its primary is connected to an $AC$ source of voltage $V$. Then,

• A. Current through its secondary is about four times that of the current through its primary
• B. Voltage across its secondary is about four times that of the voltage across its primary
• C. Voltage across its secondary is about two times that of the voltage across its primary
• D. Voltage across its secondary is about times that of the voltage across its primary

Answer 1

Answer: (A)

Current through its secondary is about four times that of the current through its primary

Answer 2

For a transformer, ratio of voltages in primary and secondary can be written as
$\frac{V_{1}}{V_{2}}=\frac{N_{1}}{N_{2}}=\frac{I_{2}}{I_{1}}$
$\Rightarrow \frac{I_{2}}{I_{1}}=\frac{4 N_{2}}{N_{2}}=4$
$\Rightarrow I_{2}=4 I_{1}$