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

This question was previously asked in
ESE Electronics 2011 Paper 1: Official Paper
View all UPSC IES Papers >
  1. 83.88° 
  2. 83.66° 
  3. 84.86°
  4. 84.08° 

Answer (Detailed Solution Below)

Option 2 : 83.66° 
Free
ST 1: UPSC ESE (IES) Civil - Building Materials
20 Qs. 40 Marks 24 Mins

Detailed Solution

Download Solution PDF

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.

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,

α = 90 – θi

α = 90 – 6.34o

α = 83.66o

Note: Brewster angle does not affect S polarized waves.

Latest UPSC IES Updates

Last updated on Jul 2, 2025

-> ESE Mains 2025 exam date has been released. As per the schedule, UPSC IES Mains exam 2025 will be conducted on August 10. 

-> UPSC ESE result 2025 has been released. Candidates can download the ESE prelims result PDF from here.

->  UPSC ESE admit card 2025 for the prelims exam has been released. 

-> The UPSC IES Prelims 2025 will be held on 8th June 2025.

-> The selection process includes a Prelims and a Mains Examination, followed by a Personality Test/Interview.

-> Candidates should attempt the UPSC IES mock tests to increase their efficiency. The UPSC IES previous year papers can be downloaded here.

More Plane Wave At Oblique Incidence Questions

Hot Links: teen patti pro yono teen patti teen patti circle teen patti gold online