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Question
State one factor on which a critical angle for a given pair of media depends. The critical angle for the glass-air interface is 45° for the yellow light. Will it be equal to, less than or greater than 45° for (i) red light, (ii) blue light?
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Solution
The value of the critical angle for a given pair of media depends on the colour of light.
(Hint: Remember VIBGYOUR Violet has minimum ic whereas Red has maximum).
(i) For red light, the critical angle will be greater than 45°.
(ii) For blue light, the critical angle will be less than 45 °.
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