O-LevelPhysicsLight5054/11 · Oct/Nov 2017 · Q201 Mark
A solid plastic cylinder is immersed in a liquid of refractive index 1.4. Light travelling in the plastic cylinder strikes the inside surface at an angle of incidence of 70°. The light undergoes total internal reflection. What are the values of the critical angle in the plastic and the refractive index of the plastic?
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Acritical angle in plastic: greater than 70°, refractive index of plastic: greater than 1.4
Bcritical angle in plastic: greater than 70°, refractive index of plastic: less than 1.4
Ccritical angle in plastic: less than 70°, refractive index of plastic: greater than 1.4
Dcritical angle in plastic: less than 70°, refractive index of plastic: less than 1.4
✓ Correct answer
C: critical angle in plastic: less than 70°, refractive index of plastic: greater than 1.4
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