A ray of light incident normally on a prism of 60 degree angles .Show the path of the light ray till it emerges out of the prism. The critical angle of glass is 42 degree

Asked by paldebtaru | 19th Jun, 2021, 08:21: AM

Expert Answer:

Light ray incident normally on side of prism at A . As seen from figure , light ray incident with angle of incidence 60o at B on oposite side .
 
Since angle of incidence is greater than critical angle , total internal reflection is taking place at B. 
Hence light ray is reflected at B with angle of reflection 60o .
 
As can be seen from figure , reflected light ray makes normal incidence  at C on third side of prism .
Hence the light ray emerges out of the prism by making angle 90o with the third side of prism.
 
Conclusion :-
If light ray makes normal incidence at one side , then it emerges out from third side by making 90o with third side .
 
Overall deviation is 60o

Answered by Thiyagarajan K | 19th Jun, 2021, 09:24: AM