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8.3 Power and efficiency

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Question 57
H

A machine has an input power of 800 W and a useful power output of 600 W. It is modified so that the wasted power is halved while the useful power is unchanged. What is the new efficiency, to two significant figures?

[1]
A

86%86\%86%

B

38%38\%38%

C

88%88\%88%

D

75%75\%75%

Markscheme

8.3 Power and efficiency Questions

  1. GCSE
  2. /Physics
  3. /8.3 Power and efficiency

128 exam-style questions on Edexcel GCSE Physics 8.3 Power and efficiency, covering 8.3.1 Power and 8.3.2 Efficiency. Each one has a worked solution and a mark scheme showing where the marks go.

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