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Question : 28
Total: 29
Describe briefly how an unpolarized light gets linearly polarized when it passes through a polaroid.
(b) Three identical polaroid sheetsP 1 , P 2 P 3 P 2 P 3 60 ∘ 90 ∘ P 1 S I 0 P 1 O 1 , O 2 O 3
OR
(a) Use Huygens geometrical construction to show how a plane wave-front att = 0
(b) Verify, using Huygens principle, Snell's law of refraction of a plane wave propagating from a denser to a rarer medium.
(c) When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same frequency. Explain why.
(b) Three identical polaroid sheets
OR
(a) Use Huygens geometrical construction to show how a plane wave-front at
(b) Verify, using Huygens principle, Snell's law of refraction of a plane wave propagating from a denser to a rarer medium.
(c) When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same frequency. Explain why.
Solution:
Ans. OR
(a)m
XY
AB
CD
v 1
v 2
∠ PAN = ∠ i = angle of incidence
= ∠ BAC
∠ RCN ′ ′ = ∠ r = angle of refraction
= ∠ ACD
In△ ABC
s i n i =
=
In△ ACD
s i n i =
=
∴
=
Refractive index of rarer medium with respect to denser medium.
This Snell's law of refraction.
(c) Reflection and refraction occur due to the interaction of light with the atoms / molecules of the media which vibrate with the same frequency of the incident light. For this the reflected and refracted light have the same frequency as that of incident light.
(a)
(b) Proof of Snell's law of refraction:
In
In
Refractive index of rarer medium with respect to denser medium.
This Snell's law of refraction.
(c) Reflection and refraction occur due to the interaction of light with the atoms / molecules of the media which vibrate with the same frequency of the incident light. For this the reflected and refracted light have the same frequency as that of incident light.
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