Exam-style question
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What is the efficiency of a transformer if the useful power output is 1500 W and the total power input is 2000 W?.
- A.75%
- B.80%
- C.85%
- D.90%
Model answer
What a good answer should say
- 75%
Explanation
Why this works
Efficiency is calculated using the formula: efficiency = (useful output / total input) x 100. Substituting the values, we have efficiency = (1500 W / 2000 W) x 100 = 75%.
This shows that 75% of the input power is converted to useful output.
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