A light ray, going through a prism with the angle of prism 60°, is found to deviate by 30°. What limit on the refractive index can be put from these data?

Angle of prism =A =


Angle of deviation=


We know that;


Angle of minimum deviation is given by =




One ray is found to be deviated by. So, the angle of minimum deviation should be either less than or equal to It should not be more than


So,


Or,



So, limit on the refractive index =.


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