question_answer

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

Correct Answer: A

Solution :

For a transformer, ratio of voltages in primary and secondary can be written as \[\frac{{{V}_{1}}}{{{V}_{2}}}=\frac{{{N}_{1}}}{{{N}_{2}}}=\frac{{{I}_{2}}}{{{I}_{1}}}\] \[\Rightarrow \] \[\frac{{{I}_{2}}}{{{I}_{1}}}=\frac{4{{N}_{2}}}{{{N}_{2}}}=4\] \[\Rightarrow \] \[{{I}_{2}}=4{{I}_{1}}\]