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

Question

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 (A) 95 % (B) 90 % (C) 88 % (D) 40 %

Tardigrade Admin · Accepted Answer

P text input =V I=220 × 5=1100 W P text output =11 V × 90 A =990 W Efficiency =( text Power output / text Power input )=(990/1100) × 100 %=90 %

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

$95%$

$90%$

$88%$

$40%$

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

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

95%

90%

88%

40%