Physics
The critical angle for glass-air is 45° for the light of yellow colour. State whether it will be less than, equal to, or more than 45° for
(i) red light,
(ii) blue light ?
Refraction Plane Surfaces
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Answer
As the wavelength of light decreases (or increases) refractive index becomes more (or less) and critical angle becomes less (or more).
(i) As the wavelength for red light is more than that for yellow colour, the refractive index becomes less and the critical angle will be more than 45°.
(ii) As the wavelength for blue light is less than that for yellow colour, the refractive index becomes more and the critical angle will be less than 45°.
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