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7.2 Power and efficiency

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Question 10
F

An electric motor is supplied with 4.0 kJ of energy. The motor wastes 1200 J of this energy.

What is the efficiency of the motor?

[1]
A

0.300.300.30

B

0.430.430.43

C

0.700.700.70

D

2.32.32.3

Markscheme

7.2 Power and efficiency Questions

  1. GCSE
  2. /Physics
  3. /7.2 Power and efficiency

50 exam-style questions on OCR GCSE Physics 7.2 Power and efficiency, covering 7.2.1 Dissipation of energy, 7.2.2 Energy transfers in domestic devices, 7.2.3 Power ratings of domestic appliances, 7.2.4 Efficiency of energy transfers, 7.2.5 Ways to increase efficiency, 7.2.6 Reducing unwanted energy transfers, and 7.2.7 Thermal conductivity and the cooling of buildings. Each one has a worked solution and a mark scheme showing where the marks go.

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