If a lamp transforms 120 joules of energy into light and heat every 2 seconds, how much power does it use?
A) 240 W
B) 480 W
C) 120 W
D) 60 W

Question

If a lamp transforms 120 joules of energy into light and heat every 2 seconds, how much power does it use? 
A) 240 W 
B) 480 W
C) 120 W
D) 60 W

Quizplus · Accepted Answer

Power is defined as the rate of energy transfer, calculated as energy divided by time. Here, 120 joules of energy are used every 2 seconds, so the power is $ \frac{120 \, \text{joules}}{2 \, \text{seconds}} = 60 \, \text{watts} $.

If a Lamp Transforms 120 Joules of Energy into Light