1. Tardigrade
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  4. A step-down transformer is employed to reduce the main supply of 220 V to 11 V. The primary draws 5 A of current and the secondary draws 90 A. The efficiency of the transformer is

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Q. A step-down transformer is employed to reduce the main supply of $220 V$ to $11 V$. The primary draws $5 A$ of current and the secondary draws $90 A.$ The efficiency of the transformer is

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Solution:

$P_{\text {input }}=V I=220 \times 5=1100 W$
$P_{\text {output }}=11 V \times 90 A =990 W$
Efficiency $=\frac{\text { Power output }}{\text { Power input }}=\frac{990}{1100} \times 100 \%=90 \%$