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Question
Name the factors affecting the critical angle for the pair of media.
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Solution
Factors affecting the critical angle are:
- Colour (or wavelength) of light: The refractive index of a transparent medium is most for violet light and least for red light; therefore, the critical angle for a pair of media is least for violet light and most for red light. Thus, the critical angle increases with increase in wavelength of light.
- Temperature: On increasing the temperature of the medium, its refractive index decreases, so the critical angle for that pair of media increases. Thus, the critical angle increases with increase in temperature
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