Optics Question 862

Question: A light of wavelength $ 6000\overset{o}{\mathop{A}} $ shines on two narrow slits separated by a distance 1.0 mm and illuminates a screen at a distance 1.5 m away. When one slit is covered by a thin glass plate of refractive index 1.8 and other slit by a thin glass plate of refractive index $ \mu $ , the central maxima shifts by 0.1 rad. Both plates have the same thickness of 0.5 mm. The value of refractive index $ \mu $ of the glass is

Options:

A) 1.4

B) l5

C) 1.6

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

[c] Change in path difference for any point on screen is $ |\mu -1.8|t. $

For central maxima, phase difference = 0. Hence, $ d\sin \theta -|\mu -1.8|t=0 $

$ \Rightarrow d\theta =|\mu -1.8|t $ [q is very small and is in radian]

$ \Rightarrow | \mu -. 1.8 | .=\frac{{{10}^{-3}}\times 0.1}{0.5\times {{10}^{-3}}}=0.2\Rightarrow \mu =2 $ or 1.6



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक