JEE PYQ: Current Electricity Question 24
Question 24 - 2020 (05 Sep 2020 Shift 1)
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:
(1) 72%
(2) 91%
(3) 85%
(4) 96%
Show Answer
Answer: (2)
Solution
Power $P = 1$ kW $= 1000$ W, $V = 220$ V, $R = 2,\Omega$. $I = \frac{P}{V} = \frac{1000}{220}$. $P_{\text{loss}} = I^2 R = \left(\frac{1000}{220}\right)^2 \times 2$. Efficiency $= \frac{1000}{1000 + P_{\text{loss}}} \times 100 \approx 96%$.
BETA
