Edexcel IGCSE Physics · Spec 4.8-4.10
Efficiency & Sankey Diagrams
Efficiency, and how to draw and read Sankey diagrams.
Physics revision video
Efficiency & Sankey Diagrams
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Spec 4.8-4.10
What you need to know
- Calculate efficiency
- Interpret a Sankey diagram
- Explain how to reduce wasted energy
Active recall
Quick check
Answer each question before opening the answer.
What is the equation for efficiency?
Efficiency = (useful energy output ÷ total energy input) × 100%.
What does a Sankey diagram show?
The energy transfers in a device, with the width of each arrow proportional to the energy (useful versus wasted).
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