WAEC - Physics (1994 - No. 22)
A lamp marked 100W, 250V is lit for 10 hours. If it operates normally and 1KWh of electrical energy costs 2k, what is the cost of lighting the lamp?
1k
2k
5k
10k
20k
Forklaring
100W X 10h = 1000Wh = 1KWh thus cost is 2k