An electric power line having total resistance of delivers 1 kW of power at 250 V. The percentage efficiency of transmission line is [2026]

Question

An electric power line having total resistance of $2 Ω,$ delivers 1 kW of power at 250 V. The percentage efficiency of transmission line is ________. [2026]

Smart Achievers · Accepted Answer

(1)

$P_{out} = 1000 W$

$P = V I$

$1000 = 250 \times I$

$I = 4 A$

$P_{loss} = I^{2} R = {(4)}^{2} \times 2 = 3200$

$P_{net} = 1000 + 32 = 103200$

$η = (\frac{P_{out}}{P_{net}}) \times 100 = \frac{1000}{1032} \times 100 = 96.9 %$

Solution

Q.
An electric power line having total resistance of $2 Ω,$ delivers 1 kW of power at 250 V. The percentage efficiency of transmission line is ________. [2026]

1 96.9

2 92.5

3 100

4 86.5

Ans.
(1)

$P_{out} = 1000 W$

$P = V I$

$1000 = 250 \times I$

$I = 4 A$

$P_{loss} = I^{2} R = {(4)}^{2} \times 2 = 3200$

$P_{net} = 1000 + 32 = 103200$

$η = (\frac{P_{out}}{P_{net}}) \times 100 = \frac{1000}{1032} \times 100 = 96.9 %$

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