Comparing Bulbs
Science: KS3, topic 3.1.16
Comparing Bulbs
Old filament bulbs had a power rating of 60W. An eco-friendly energy saving light bulb has a power rating of 15W. If both bulbs were turned on for one minute, how much energy would be transferred?
Converting minutes to seconds
- Time needs to be calculated in seconds, not minutes.
- So one minute needs to be converted to 60 seconds.
Filament bulb calculation
- Energy transferred = power (W) × time (s).
- Energy transferred = 60 x 60 = 3600J.
Energy saving bulb calculation
- Energy transferred = power (W) × time (s).
- Energy transferred = 15 x 60 = 900J.
Test yourself on Comparing Bulbs
What is the power rating of an old filament light bulb?
What is the power rating of an eco-friendly light bulb?
A 60W filament bulb and a 15W eco bulb are both switched on for the same length of time. Which bulb transfers more energy?