Question

Question 8

A 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)

a. How much energy is used by the lightbulb? (2 points)

b. How much energy is used by the toaster oven? (2 points)

c. The lightbulb has an efficiency of 2.3%. How much light energy does the lightbulb produce in 16 hours? (2 points)

Answer 1

Step-by-step explanation:

a) power = energy/time

taking time in seconds: 16 x 60 min x 60 sec =57600 s

now:

60 W = E/57600 s

E = 3456000 J or 3456 KJ

b) time: 45 x 60 s = 2700 s

P = E/t

1500 W = E/2700

E = 4050000 J or 4050 KJ

c) efficiency = (output energy/input energy) x 100

2.3% = (X/3456000) x 100

X = (2.3/100) x 3456000

X = 79488 J