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GUJCET · Physics · Current Electricity
If the electric current in a lamp decreases by 5% then the power output decreases by _________.
- A \(5 \%\)
- B \(20 \%\)
- C \(2.5 \%\)
- D \(10 \%\)
Answer & Solution
Correct Answer
(D) \(10 \%\)
Step-by-step Solution
Detailed explanation
(D)
\( P = I ^2 R \\ d P =2 I (d) R \\ \frac{d P }{ P } =\frac{2 I d R }{ I ^2 R } \\ \frac{d P }{ P } =2 \frac{d I }{ I }\)
\( \frac{d P }{ P } \times 100 =2 \frac{d l }{ I } \times 100 \\ =2(5 \%) \\ =10 \%\)
\( P = I ^2 R \\ d P =2 I (d) R \\ \frac{d P }{ P } =\frac{2 I d R }{ I ^2 R } \\ \frac{d P }{ P } =2 \frac{d I }{ I }\)
\( \frac{d P }{ P } \times 100 =2 \frac{d l }{ I } \times 100 \\ =2(5 \%) \\ =10 \%\)
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