Edexcel IGCSE Physics · Spec 3.18-3.20
Refractive Index: Using the Equations
Worked examples using the refractive index equations.
Physics revision video
Refractive Index: Using the Equations
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Spec 3.18-3.20
What you need to know
- Use n equals sine i over sine r
- Rearrange it to find an unknown angle
- Use sine c equals one over n to find the critical angle
Active recall
Quick check
Answer each question before opening the answer.
Give the refractive index equation using angles (Snell's law).
n = sin i ÷ sin r.
How is refractive index linked to the critical angle?
n = 1 ÷ sin c, where c is the critical angle.
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