Alternating Current Ques 29
29. A transformer having efficiency of $90 \%$ is working on $200 $ $V$ and $3 $ $kW$ power supply. If the current in the secondary coil is $6 $ $A$, the voltage across the secondary coil and the current in the primary coil respectively are :
[2014]
(a) $300$ $ V, 15$ $ A$
(b) $450$ $ V, 15 $ $A$
(c) $450 $ $V, 13.5 $ $A$
(d) $600$ $ V, 15 $ $A$
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Answer:
Correct Answer: 29.(b)
Solution:
- (b) Efficiency $\eta=\frac{V_s I_s}{V_p I_p} \Rightarrow 0.9=\frac{V_s(6)}{3 \times 10^{3}}$
$\Rightarrow V_s=450 $ $V$
As $V_p I_p=3000$ so,
$I_p=\frac{3000}{V_p}=\frac{3000}{200} A=15$ $ A$
BETA
