Alternating Current Ques 33
33. A transformer is used to light a $100 $ $W$ and $110 $ $V$ lamp from a $220$ $ V$ mains. If the main current is $0.5$ $ amp$, the efficiency of the transformer is approximately
[2007]
(a) $50 \%$
(b) $90 \%$
(c) $10 \%$
(d) $30 \%$.
Show Answer
Answer:
Correct Answer: 33.(b)
Solution:
- (b) Efficiency of the transformer
$\eta=\frac{P _{\text{output }}}{P _{\text{input }}} \times 100=\frac{100}{220 \times 0.5} \times 100=90.9 \%$
BETA
