AQA GCSE PHYSICS · PAPER 1 · FOUNDATION & HIGHER
Exam Practice: Energy transfers in everyday appliances
Energy transfers in everyday appliances · Electricity · Lesson 7 of 10 · 14 marks · 15 minutes
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Instructions
• Answer all the questions.
• Write your answers in the spaces provided.
• The marks for each question are shown in brackets - use this as a guide to how much to write.
• The answers are on separate pages at the back. Attempt every question before you look at them.
• Answer all questions. Use the mark allocation as a guide to how much to write.
Question 1 CALCULATE (3 marks)
A kettle has a power of 2000 W. It is switched on for 3.0 minutes. Calculate the energy transferred by the kettle. Use the equation: energy transferred = power × time
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(Total for Question 1 = 3 marks)
Question 2 CALCULATE (2 marks)
A charge of 500 C flows through a motor connected to a 12 V battery. Calculate the energy transferred to the motor. Use the equation: energy transferred = charge flow × potential difference
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(Total for Question 2 = 2 marks)
Question 3 DESCRIBE (2 marks)
Describe the main energy transfer when an electric drill is used.
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(Total for Question 3 = 2 marks)
Question 4 EXPLAIN (3 marks)
A hair dryer has a power of 1500 W. A phone charger has a power of 10 W. Explain why the hair dryer transfers more energy in one minute.
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(Total for Question 4 = 3 marks)
Question 5 CALCULATE (4 marks)
A 3.0 kW electric shower is used for 8.0 minutes. Calculate the energy transferred in megajoules (MJ).
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(Total for Question 5 = 4 marks)
TOTAL FOR PAPER = 14 MARKS
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Answers and mark scheme
Check your answer only once you have written one.
Question 1 (3 marks)
t = 180 s; E = 2000 × 180 = 360 000 J
• Converts to 180 s 1 mark
• Correct substitution 1 mark
• 360 000 J 1 mark
Question 2 (2 marks)
E = 500 × 12 = 6000 J
• Correct substitution 1 mark
• 6000 J 1 mark
Question 3 (2 marks)
Electrical energy from the mains is transferred to the kinetic energy store of the drill bit (and some to the thermal store and sound).
• Electrical energy transferred 1 mark
• To the kinetic store of the drill 1 mark
Question 4 (3 marks)
Power is the energy transferred each second, so 1500 W transfers 1500 J each second and 10 W transfers 10 J each second. In the same time the hair dryer transfers much more energy.
• Power is energy transferred per second 1 mark
• 1500 J each second and 10 J each second 1 mark
• Same time so hair dryer transfers more 1 mark
Question 5 (4 marks)
P = 3000 W; t = 480 s; E = 1 440 000 J = 1.44 MJ
• Converts to 3000 W 1 mark
• Converts to 480 s 1 mark
• 1 440 000 J 1 mark
• 1.44 MJ 1 mark