# Two cities are 150km 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: Option 1) 19.2W Option 2) 19.2kW Option 3) 19.2J Option 4) 12.2kW

P Prateek Shrivastava

Power dissipiated in external resistance -

$P=(\frac{E}{R+r})^{2}R$

-

Power loss=$\frac{V^{2}}{R}$

$V= 8 \times 150\:V=1200\:Volt$

$R= 0.5 \Omega /km \times 150=75 \Omega$

Power loss= $\frac{V^{2}}{R}-\frac{(1200)^{2}}{75}W=19.2 kW$

Option 1)

19.2W

This option is incorrect.

Option 2)

19.2kW

This option is correct.

Option 3)

19.2J

This option is incorrect.

Option 4)

12.2kW

This option is incorrect.

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