This deep dive covers Understanding 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 2 of 12 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 2 of 12
Practice
14 questions
Recall
25 flashcards
💡 Understanding Power
Figure 1: The power formula triangle — cover the quantity you want to find
Power is defined as the rate of energy transfer or the rate of doing work. It tells you how many joules of energy are transferred every second.
P = E / t Power (W) = Energy transferred (J) ÷ Time (s)
This can also be written as:
P = W / t Power (W) = Work done (J) ÷ Time (s)
Both equations mean the same thing — "work done" and "energy transferred" are interchangeable in this context.
- Power is measured in watts (W) — named after James Watt, who improved the steam engine
- 1 watt = 1 joule per second (1 W = 1 J/s)
- Higher power means energy is transferred more quickly
- Power does NOT tell you how much total energy was used — only how fast it was used
Quick Check: A motor transfers 600 J of energy in 30 seconds. What is its power output?
P = E / t = 600 ÷ 30 = 20 W. The motor has a power output of 20 watts.