Question

A transformer is used to light a 100W , 110V lamp from a 220V mains . If the main current is 0.5 A the efficiency of the transformer is approximately
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Answer 1

Answer:

Given,

The mains current is 0.5A.

The mains voltage is 220V.

Power of light =100Wand voltage V=110V

The efficiency is n=  

input

output

​  

×100=  

220×0.5

100

​  

×100=90.9

The approximate efficiency of transformer is 90%.