KCET · Physics · Alternating Current
A step-down transformer reduces the voltage of a transmission line from \(2200 \mathrm{~V}\) to \(220 \mathrm{~V}\). The power delivered by it is \(880 \mathrm{~W}\) and its efficiency is \(88 \%\). The input current is
- A \(4.65 \mathrm{~mA}\)
- B \(0.045 \mathrm{~A}\)
- C \(0.45 \mathrm{~A}\)
- D \(4.65 \mathrm{~A}\)
Answer & Solution
Correct Answer
(C) \(0.45 \mathrm{~A}\)
Step-by-step Solution
Detailed explanation
Efficiency of transformer,
\(eta \eta =\frac{\text { Output po }}{\text { Input powe }} \)
\( \Rightarrow \frac{88}{100} =\frac{880}{P_{i}} \)
\( \Rightarrow P_{i} =1000 \mathrm{~W} \)
\( \text { Input current, } I_{P} =\frac{P_{i}}{V_{i}} \)
\( =\frac{1000}{2200} \)
\( =0.45 \mathrm{~A}\)
\(eta \eta =\frac{\text { Output po }}{\text { Input powe }} \)
\( \Rightarrow \frac{88}{100} =\frac{880}{P_{i}} \)
\( \Rightarrow P_{i} =1000 \mathrm{~W} \)
\( \text { Input current, } I_{P} =\frac{P_{i}}{V_{i}} \)
\( =\frac{1000}{2200} \)
\( =0.45 \mathrm{~A}\)
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