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GCSE Physics · key term
The angle of incidence in the higher-refractive-index material for which the angle of refraction is 90°.
Used by Edexcel
Specification 5.1P · Paper 1
Revise: Ray Diagrams and TIRIf the angle of incidence is increased beyond the critical angle, no refracted ray passes into the second material. All the incident light is reflected back inside the original material. This is total internal reflection, or TIR.
At the critical angle, the refracted ray travels along the boundary. Total internal reflection occurs only when the angle of incidence is greater than the critical angle.
For total internal reflection, state both conditions: light travels from a higher refractive index to a lower refractive index, and the angle of incidence exceeds the critical angle.
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