Current Electricity - Result Question 64
69. Two cities are $150 km$ apart. Electric power is sent from one city to another city through copper wires. The fall of potential per $km$ is 8 volt and the average resistance per $km$ is $0.5 \Omega$. The power loss in the wires is :
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======= ####69. Two cities are $150 km$ apart. Electric power is sent from one city to another city through copper wires. The fall of potential per $km$ is 8 volt and the average resistance per $km$ is $0.5 \Omega$. The power loss in the wires is :
c3eec34ec6b1fad69db54a20ad4b2dca40c2aa54 (a) $19.2 W$
(b) $19.2 kW$
(c) $19.2 J$
(d) $12.2 kW$
[2014]
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Answer:
Correct Answer: 69. (b)
Solution:
- (b) Total resistance $R=(0.5 \Omega / km) \times(150 km)$ $=75 \Omega$
Total voltage drop $=(8 V / km) \times(150 km)=1200 V$
Power loss $=\frac{(\Delta V)^{2}}{R}=\frac{(1200)^{2}}{75} W$
$=19200 W=19.2 kW$
