QJEEM20Phece9: JEE Main 2020 Physics - Class 12 JEEM20Phece9 Solution: An electrical power line, having a total resistance of 2 Ω ,…

Question

Verified Solution • 2025–26 Session moderate

An electrical power line, having a total resistance of 2

Ω

, delivers 1 kW at 220 V. The efficiency of the transmission line is approximately :

Accepted Answer

We know,

η = \frac{P_{o u t}}{(P_{o u t} + P_{l o s s})} \times 100

Given, P=

v i = 10^{3}

∴

i = \frac{1000}{220}

=

\frac{50}{11}

A

Power

l o s s = i^{2} R = {(\frac{50}{11})}^{2} \times 2

∴

efficiency

= \frac{1000}{1000 + i^{2} R} \times 100 = 96 %

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