This topic summary covers Topic Summary: Power within Power for GCSE Physics. Revise Power in Energy for GCSE Physics with 14 exam-style questions and 25 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 12 of 12 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 12 of 12
Practice
14 questions
Recall
25 flashcards
Topic Summary: Power
Key Equations
- P = E/t — power from energy and time
- P = W/t — power from work done and time
- P = IV — electrical power
- P = I²R — electrical power (current + resistance)
- P = V²/R — electrical power (voltage + resistance)
- Energy (kWh) = Power (kW) × Time (h)
Key Terms
- Power — rate of energy transfer
- Watt (W) — 1 J/s
- Kilowatt (kW) — 1,000 W
- Kilowatt-hour (kWh) — unit of energy (not power)
Unit Conversions
- 1 kW = 1,000 W
- 1 MW = 1,000,000 W
- 1 kWh = 3,600,000 J
- Minutes → seconds: × 60
- Hours → seconds: × 3,600
Common Pitfalls
- kWh is energy, not power
- Always convert time to seconds for P = E/t
- Higher power ≠ more total energy used
- Power is a scalar (no direction)