Two cities are 150 k m apart. Electric power is sent from one city to another city through copper wires. The…

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 volts and the average resistance per km is 0.5 Ω. The power loss in the wire is:
  1. 19.2 W
  2. 19.2 kW
  3. 19.2 J
  4. 12.2 kW

Solution

Distance between the two cities, 150 km.

Voltage drop per kilometre is 8 V km-1.

Resistance per kilometre 0.5 Ω km-1

Total voltage drop will be,
Vdrop=150 km×8 V km-1=1200 V

Total resistance of wire, 
R=0.5 Ω km-1×150 km=75 Ω

Therefore, the power loss will be, P=V2R=150×820.5×150=19.2 kW

Asked in: NEET 2014

Practice more Current Electricity questions on Aicharya