Power loss on electric circuit?
A 110 volt direct current generator supplies a 1000 watt floodlight through 50 metres of two core cable. If the voltage at the lamp is not to be less than l05 volts:
(a) What is the current flowing?
(b) What is the total power loss in the cable?
(c) What is the maximum resistance per metre of each core of the cable?
Please show with workings
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(a) Assuming that 1000 watts is actually consumed by the lamp, then 9.524A will be flowing in the circuit. (1000 / 105)
(b) 5 volts is dropped across the cable, so 9.524 x 5 = 47.61 watts is lost in the cable
(c) There is a total of 100m of cable, and the total resistance is 5^2 / 47.61 = 0.525 ohms, so the resistance per metre is 0.525 / 100 = 0.00525 ohms per metre.