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JEE Main 2020 (5 Sep, Shift 1) · Electrical Power & Heating Effect

Electrical Power & Heating Effect question from JEE Main 2020 (5 Sep, Shift 1)

Q38JEE Main 2020 · 5 SEP · SHIFT 1Medium

Electrical Power & Heating Effect

An electrical power line, having a total resistance of 2 $\Omega$ , delivers 1 kW at 220 V. The efficiency of the transmission line is approximately:

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Answer: (b)

$I = P/V = 1000/220 = 4.55\text{ A}$ .
Line loss: $I^2 R = (4.55)^2 \times 2 \approx 41.3\text{ W}$ .
$\eta = \dfrac{1000}{1041.3} \times 100 \approx 96\%$ .
So the answer is (b) 96%.

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