F1 Tapesh 9.12.20 Pallavi D14

plane wave is generated under water (ϵ = 81 ϵ0 and μ = μ0) The wave is parallel polarized. At the interface between water and air, the angle a for which there is no reflection is

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  1. 83.88° 
  2. 83.66° 
  3. 84.86°
  4. 84.08° 

Answer (Detailed Solution Below)

Option 2 : 83.66° 
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Detailed Solution

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Concept:

Brewster’s Angle:  Brewster's angle is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection.

\(tan{\theta _i} = \sqrt {\frac{{{ϵ_2}}}{{{ϵ_1}}}} - - - \left( 1 \right)\)

Calculation:

For no reflection incident wave should be completely transmitted to another medium at Brewster angle.

Given:

ϵ2 = ϵ0, ϵ1 = 81ϵ0 

From (1) we get,

\(tan{\theta _i} = \sqrt {\frac{{{\epsilon_0}}}{{81{\epsilon_0}}}} \)

\({\theta _i} = {\tan ^{ - 1}}\frac{1}{9} = {6.34^o}\)

α = 90 – θi

α = 90 – 6.34o

α = 83.66o

Note: Brewster angle does not affect S polarized waves.

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