Answer:
13.3 seconds
Explanation:
The complete question is...
How long does it take a 75 W lightbulb to use 1 kJ of energy?
The Energy of the bulb E = 1 KJ = 1000 J
The power rating of the lightbulb = 75 W
The power rating of a bulb P = Energy used per unit time = E/t
substituting, we have
75 = 1000/t
t = 1000/75 = 13.3 seconds
