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[add image: a ray of white light enters glass from air through a curved surface, splitting into a spectrum with green marked at the top, exiting through a lower surface] Which set of colours will come out in air for a situation shown in figure?
A
Yellow, Orange and Red
B
All
C
Orange, Red and Violet
D
Blue, Green and Yellow
Detailed Solution
The critical angle $\sin i_c=\dfrac{1}{\mu}\propto\lambda$ (critical angle increases with wavelength, since $\mu$ decreases with increasing wavelength). At the given angle of incidence inside the glass, only colours with a sufficiently large critical angle (i.e., longer wavelengths — yellow, orange and red) can emerge into air without undergoing total internal reflection.