This definitions covers Key Definitions within Electrical Power & Energy for GCSE Physics. Revise Electrical Power & Energy in Electricity for GCSE Physics with 15 exam-style questions and 30 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 7 of 15 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Definitions
Power (P): The rate of energy transfer — the energy transferred per second. Measured in watts (W). 1 W = 1 J/s.
Watt (W): The SI unit of power. 1 watt = 1 joule of energy transferred per second.
Kilowatt (kW): 1000 watts. Used for high-power appliances.
Kilowatt-hour (kWh): The unit of energy used on electricity bills. Energy used by a 1 kW appliance running for 1 hour. 1 kWh = 3,600,000 J.
Energy transferred (E): Total energy transferred by an appliance. E = P × t. Measured in joules (J) or kWh.
Practice questions for Electrical Power & Energy
What is the unit of electrical power?
Explain why the National Grid transmits electricity at high voltage to reduce energy losses.