Question 489: AC fundamentals

Question

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

Accepted Answer

Efficiency of the transformer
= $${{{P_{output}}} \over {{P_{input}}}} 	imes 100$$
= $${{100} \over {220 	imes 0.5}} 	imes 100$$ = 90 %

Answer

50%

Answer

90%

Answer

10%

Answer

30%

AC fundamentals

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

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