Alternating Current Ques 31
31. A $220$ volts input is supplied to a transformer. The output circuit draws a current of $2.0$ ampere at $440$ volts. If the efficiency of the transformer is $80 \%$, the current drawn by the primary windings of the transformer is
[2010]
(a) $3.6$ ampere
(b) $2.8$ ampere
(c) $2.5$ ampere
(d) $5.0$ ampere
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Answer:
Correct Answer: 31.(d)
Solution:
- (d) $\frac{V_2}{V_1}=0.8 \frac{I_1}{I_2} \Rightarrow \frac{V_2 I_2}{V_1 I_1}=0.8$
$V_1=220$ $ V, I_2=2.0 $ $A, V_2=440 $ $V$
$I_1=\frac{V_2 I_2}{V_1} \times \frac{10}{8}=\frac{440 \times 2 \times 10}{220 \times 8}=5 $ $A$
BETA
