Question

A beam of light $AO$ is incident on a glass slab $(\mu =1.54)$ in a direction as shown in figure. The reflected ray $OB$ is passed through a Nicol prism on viewing through a Nicole prism, we find on rotating the prism that

• A. The intensity is reduced down to zero and remains zero
• B. The intensity reduces down somewhat and rises again
• C. There is no change in intensity
• D. The intensity gradually reduces to zero and then again increases

Answer 1

Answer: (D)

In the arrangement shown, the unpolarised light is incident at polarising angle of $90^{\circ }-33^{\circ }=57^{\circ }.$ The reflected light is thus plane polarised light. When plane polarised light is passed through Nicol prism (a polariser or analyser), the intensity gradually reduces to zero and finally increases.