give reasons

Asked by sumahr | 5th Nov, 2009, 10:06: AM

Expert Answer:

When a ray of unpolarised light enters the nicol prism, it is plit into o -ray and e - ray. Velocity of o-ray is same whatever its direction of propagation may be but the velocity of e - ray depends upon its direction of propagation. As the e ray deviated from the optical axis, its velocity increases and is max. while propagating at right angles to the optic axis when μe = 1.486. Refractive index μCB = 1.550 , thus e-ray while encountering ' canada balsam ' layer ' , finds going from rare to denser medium and hence is transmitted through it. O-ray on reaching ' canada balsam ' layer ' , finds going from  denser to rare medium; if its angle of incidence , at the layer exceeds, the value of critical angle for the layer, it gets reflected back due to total internal reflection and is absorbed by the sides.

Answered by  | 5th Nov, 2009, 04:11: PM

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