A 40 kW electric cable is used to transmit electricity through a resistor of resistance 2.0Ω at 800 V. The power loss as internal energy is?
- 4.0 x 102W
- 5.0 x 102W
- 4.0 x 103W
-
5.0 x 103W
The correct answer is: D
Explanation
In general, power = IV; 40kw = IV.∴ 40,000 = 1 x 800
1 = (40.000)/800 = 50A. tune the current through resistor = 50A.
∴ power loss = 12R = 502 X 2 = 2500 X 2 = 5.0 X 103W