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Question
A green light is incident from the water to the air-water interface at the critical angle (C). Select the correct statement.
Options
The entire spectrum of visible light will come out of the water at an angle of 90° to the normal.
The spectrum of visible light whose frequency is less than that of green light will come out to the air medium.
The spectrum of visible light whose frequency is more than that of green light will come out to the air medium.
The entire spectrum of visible light will come out of the water at various angles to the normal.
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Solution
The spectrum of visible light whose frequency is less than that of green light will come out to the air medium.
Explanation:
`sin i_C = 1/n` and `n prop 1/lambda`
For greater wavelength (i.e., lesser frequency) n is less. Hence, iC would be more. Thus, these wavelengths will not suffer internal reflection and come out at angles less than 90°.
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