• # question_answer A step - down transformer, transforms a supply line voltage of 2200 V into 220V. The primary coil has 5000 turns. The efficiency and power transmitted by the transformer are $90%$ and 8 kW respectively. Then, the power supplied is: A)  $9.89$ kW                               B)  $8.89$ kW C)  $88.9$ kW                               D)  889 kW

Efficiency of transformer is given by: $\eta \,=\frac{Output\,power}{Input\,Power}$ Here, ${{P}_{Output}}=8kW,\,\,\eta \,=90%$ ${{P}_{input}}\,=\frac{8\times 100}{\,90}\,=\frac{80}{9}kW\,=8.89\,kW$