Question

a. Replacing standard incandescent lightbulbs with energy-efficient compact fluorescent lightbulbs can save a lot of energy. Calculate the amount of energy saved over 10 h when one 60 W incandescent lightbulb is replaced with an equivalent 18 W compact fluorescent lightbulb. (3 points) b. How long could you run a 300 W plasma television set on the saved energy

Answer 1

Answer:

a) 1512000 Joules

b) 5040 seconds = 84 minutes = 1.4 hours

Explanation:

a) Power saved by replacing bulbs = 60-18 = 42 W = 42 J/s

Time the bulb is used for = 10 hours

Energy saved during this time

42×10×60×60 = 1512000 Joules

Saved energy by replacing standard incandescent lightbulbs with energy-efficient compact fluorescent lightbulbs in 10 hours is 1512000 Joules

b) Power the plasma TV uses = 300 W = J/s

$\frac{1512000}{300}=5040\ s$

Time a plasma TV can be used for with the saved energy is 5040 seconds = 84 minutes = 1.4 hours.