Question
Sat June 18, 2011 By: Gurleen Kaur

A 60W electric lamp gives off energy in the form of light at a rate of 7-5 joule/second. What percentage of energy does the lamp transform into light?

Expert Reply
Sun June 19, 2011
The energy consumed by the lamp = 60 joule/sec
 
The energy transformed in the form of light = 7.5 joule/sec
 
The percentage of energy transformed  into light = 7.5 x 100/60 = 75 / 6 = 12.5 %
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