Question

A beam of light AO is incident on a glass slab ($\mu =1.54$) in a direction as shown in the diagram. The reflected ray OB is passed through a polaroid. On viewing through the polaroid, we find that on rotating the polaroid. (Given $tan{57}^0=1.54$)

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

Answer 1

The correct option is D The intensity gradually reduces to zero and then again increases.

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