Optics Question 567

Question: In the visible region of the spectrum the rotation of the place of polarization is given by $ \theta =a+\frac{b}{{{\lambda }^{2}}} $ . The optical rotation produced by a particular material is found to be 30° per mm at $ \lambda =5000 $ Å and 50° per mm at $ \lambda =4000 {\AA} $ . The value of constant a will be

Options:

A) $ +\frac{50{}^\circ }{9} $ per mm

B) $ -\frac{50{}^\circ }{9} $ per mm

C) $ +\frac{9{}^\circ }{50} $ per mm

D) $ -\frac{9{}^\circ }{50} $ per mm

Show Answer

Answer:

Correct Answer: B

Solution:

$ \theta =a+\frac{b}{{{\lambda }^{2}}} $

$ 30=a+\frac{b}{{{(5000)}^{2}}} $ and $ 50=a+\frac{b}{{{(4000)}^{2}}} $ .

Solving for a, we get $ a=-\frac{50{}^\circ }{9}permm $



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