Question:
An electric power line having total resistance of \(2\,\Omega\), delivers \(1\,\text{kW}\) of power at \(250\ \text{V}\). The percentage efficiency of the transmission line is _________.
An electric power line having total resistance of \(2\,\Omega\), delivers \(1\,\text{kW}\) of power at \(250\ \text{V}\). The percentage efficiency of the transmission line is _________.
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Transmission efficiency improves when current is low, which reduces \(I^2R\) losses.
Updated On: Feb 5, 2026
- 92.5
- 96.9
- 86.5
- 100
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The Correct Option is B
Solution and Explanation
Step 1: Calculate the current in the transmission line.
\[ I = \frac{P}{V} = \frac{1000}{250} = 4\ \text{A} \]
Step 2: Find power loss in the transmission line.
\[ P_{\text{loss}} = I^2R = 4^2 \times 2 = 32\ \text{W} \]
Step 3: Calculate efficiency of transmission.
\[ \eta = \frac{P_{\text{output}}}{P_{\text{input}}}\times 100 = \frac{1000}{1000+32}\times100 \approx 96.9% \]
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