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what is the percent efficiency of a light bulb that emits 14 joules of light for every 60 joules of electric energy thst enters it?

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If you're using the bulb as a source of light, then it's. 14/60 = 23.3% efficient.
If you're using it to heat a bird nest or a hamster cage, then it's. 46/60 = 76.7% efficient !
It just depends on your point of view, and what you consider 'useful' output.
User Kristinalim
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