KVPY2020PhysicsRay Optics
A monochromatic beam of light is incident at the interface of two materials of refracive index n 1 and n 2 as shown. If n 1 > n 2 and θ c is the critical angle then which of the following statements is NOT true?
Options
- Aθ 1 = θ 3 for all values of θ 1
- Bcos θ 2 is imaginary for θ 1 > θ c
- Ccos θ 2 = 0 for θ 1 = θ c
- Dcos θ 3 is imaginary for θ 1 = θ c
Correct answer
D. cos θ 3 is imaginary for θ 1 = θ c
Step-by-step solution
n 1 > n this means light is going from rarer to denser medium. So θ 2 will always be less than θ 1 n 2 sin θ 1 = n 1 sin θ 2 So cos θ 2 will never be imaginary and also θ 2 can't be 90 ° In question incorrect options are asked. ∴ ( B , C , D )