Three Power Equations — When to Use Each
Part of Electrical Power & Energy — GCSE Physics
This deep dive covers Three Power Equations — When to Use Each 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 is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 2 of 15 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 15
Practice
15 questions
Recall
30 flashcards
📚 Three Power Equations — When to Use Each
P = IV — Use when you know current AND voltage
P = I²R — Use when you know current AND resistance (no voltage given)
P = V²/R — Use when you know voltage AND resistance (no current given)
How these all connect (combining P = IV with V = IR):
- P = IV, substitute V = IR → P = I × (IR) = I²R
- P = IV, substitute I = V/R → P = (V/R) × V = V²/R