🎯 Common Question Types:
- Calculate power from energy and time (2 marks)
- Calculate electrical energy cost in kWh and pence (3-4 marks)
- Rearrange P = E/t to find E or t (2 marks)
- Use P = IV for electrical circuits (2 marks)
- Compare power ratings of appliances (1-2 marks)
📝 Key Command Words:
- Calculate: Show all steps — write formula, substitute, give answer with units
- State: Give the definition or unit of power without explanation
- Explain: Give the reason with reference to the equation (e.g., "higher power means more energy per second because P = E/t")
- Compare: Identify which appliance has higher/lower power and what that means
⚠️ Common Mistakes to Avoid:
- Forgetting to convert minutes or hours to seconds when using P = E/t
- Mixing up energy (J) and power (W) in your answer
- Using kW instead of W in the main equation P = E/t (must use SI units)
- Forgetting that kWh is a unit of energy, not power
This exam tips covers Exam Tips for Power within Power for GCSE Physics. Revise Power in Energy for GCSE Physics with 14 exam-style questions and 25 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 11 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Practice questions for Power
Which of the following is the correct definition of power?
A microwave oven transfers 54,000 J of energy. It has a power rating of 900 W. Calculate how long the microwave was switched on. Use the equation: power = energy transferred / time Give your answer in seconds (s).
Quick recall flashcards
What is power?
Power is the rate at which energy is transferred or work is done. It is measured in watts (W).
What is mechanical power?
Mechanical power is the rate at which mechanical work is done or mechanical energy is transferred, calculated using P = W/t.