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At what angle should two polarizing filters be positioned to reduce the intensit

ID: 1528324 • Letter: A

Question

At what angle should two polarizing filters be positioned to reduce the intensity of light by 60%? Young's double slit experiment breaks a single light beam into two sources. Would the same pattern be obtained for two independent sources of light, such as the headlight of a distant car? Explain. A two-slit experiment is performed in the air. Later, the same apparatus is immersed in water and the experiment is repeated. When the apparatus is in water, are the interference fringes (a) more closely spaced (b) more widely spaced or (c) spaced the same as when the apparatus was in air? Explain.

Explanation / Answer

a) I = Io cos^2 theta

Io ( 2/5 ) = Io cos^2 theta

cos^2 theta = 2/5

cos theta= 0.632

theta = 50.768 degree apprx

b) No. becuase two different headlights belong to two differenet sources of light and interference pattern will change rapidly with time, therefore, interference will not be observed.

c)Fringe width is directly proportional to wavelength, in denser medium the wavelength will reduce, so fringe width will also be reduced.