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NTA Abhyas JEE Main2020PhysicsAlternating CurrentPractice

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 A . The efficiency of the transformer is approximately -

Options

  1. A30 %
  2. B50 %
  3. C90 %
  4. D10 %

Correct answer

C. 90 %

Step-by-step solution

Efficiency of Transformer = P o w e r o u t p u t P o w e r i n p u t % η = P o u t P i n × 100 = 100 220 × 0.5 × 100 = 90 %

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