Question

A)

An incandescent lightbulb has a power of 60 W and is used for 16 hours. A toaster oven has a power of 1500 W and is used for 45 minutes. (Use correct units in all answers.)

Part A

Which device uses more electricity, and by how much?

(2 points)

TWEE

B)

How much energy would you save in 16 hours of use by switching from the incandescent lightbulb to an LED lightbulb with a power of 12 W?

Part B

(2 points)

Part C

The LED bulb has an efficiency of 12.5%, and the incandescent bulb has an efficiency of 1.9%. Which bulb produces more light power, and by how much?

Answer 1

Part A:

Electricity used by the incandescent lightbulb = 60 W * 16 hours = 960 Wh
Electricity used by the toaster oven = 1500 W * 0.75 hours = 1125 Wh

The toaster oven uses more electricity by 1125 - 960 = 165 Wh.

Part B:

Energy saved by switching to an LED lightbulb = 960 Wh - 12 W * 16 hours = 768 Wh

Part C:

Energy produced by LED bulb = 12 W * 0.125 = 1.5 W
Energy produced by incandescent bulb = 60 W * 0.019 = 1.14 W

The LED bulb produces more light power by 1.5 - 1.14 = 0.36 W.