Bissoy.com
Doctors Medicines MCQs Q&A

There are two medium L1 and L2 of refractive index n1 and n2 respectively (n2  > n1 > 1). In which of the following condition the total internal reflection may occur: a) When the light travel from medium L1 to medium L2. b) When the light travels from medium L2 to medium L1. c) When the light travel from medium L1 to air. d) When the light travels from air to medium L2. Which of the following statement is correct?

There are two medium L1 and L2 of refractive index n1 and n2 respectively (n2  > n1 > 1). In which of the following condition the total internal reflection may occur: a) When the light travel from medium L1 to medium L2. b) When the light travels from medium L2 to medium L1. c) When the light travel from medium L1 to air. d) When the light travels from air to medium L2. Which of the following statement is correct? Correct Answer b and c are correct.

CONCEPT:

Total Internal Reflection (TIR):

[ alt="F1 P.Y Madhu 12.05.20 D1" src="//storage.googleapis.com/tb-img/production/20/05/F1_P.Y_Madhu_12.05.20_D1.png" style="width: 412px; height: 257px;">

  • When a ray of light goes from denser to the rarer medium it bends away from the normal and as the angle of incidence in the denser medium increases, the angle of refraction in the rarer medium also increases, and at a certain angle, the angle of refraction becomes 90°, this angle of incidence is called critical angle (C).
  • When the angle of incidence exceeds the critical angle than light ray comes back into the same medium after reflection from the interface. This phenomenon is called Total internal reflection (TIR).

Conditions for TIR: 

  1. The ray must travel from denser medium to rarer medium.
  2. The angle of incidence i must be greater than the critical angle C.
     
Denser Medium Rarer Medium
The denser medium will have a higher refractive index. The rarer medium will have a lower refractive index.

​
EXPLANATION:

a) When the light travel from medium L1 to medium L2

  • In this situation, light is travelling from low refractive index medium (rarer medium) to a higher refractive index medium (denser medium).
  • So total internal reflection cannot occur.

b) When the light travels from medium L2 to medium L1

  • In this situation, light is travelling from a higher refractive index medium (denser medium) to a low refractive index medium (rarer medium).
  • So total internal reflection may occur.

c) When the light travel from medium L1 to air

  • In this situation, light is travelling from a higher refractive index medium (denser medium) to a low refractive index medium (rarer medium).
  • So total internal reflection may occur.

d) When the light travels from air to medium L2

  • In this situation, light is travelling from low refractive index medium (rarer medium) to a higher refractive index medium (denser medium).
  • So total internal reflection cannot occur.

So in situation b and situation c, the total internal reflection may occur.

  • Hence, option 2 is correct.

Related Questions

For any two languages L1 and L2 such that L1 is context-free and L2 is recursively enumerable but not recursive, which of the following is/are necessarily true? I. L̅1 (complement of L1) is recursive II. L̅2 (complement of L2) is recursive III. L̅1 is context-free IV. L̅1 ∪ L2 is recursively enumerable
Choose the correct relation for a combination of two prisms to be achromatic. (Where for the first prism: μv = refractive index of the medium in violet light, μr = refractive index of the medium in red light A = angle of the prism; For the second prism: μ′v = refractive index of the medium in violet light, μ′r = refractive index of the medium in red light, A’ = angle of prism.)
A crown glass prism with refractive index 6° is to be achromatized for red and blue color light with flint glass prism. What will be the angle of flint glass prism? (µr = 1.513, µr‘ = 1.645, µ2 = 1.523 and µ2‘ = 1.665, Where µr and µ2 are refractive indices of red and blue light respectively whereas, µr‘ and µ2‘ are refractive indices of red and blue light respectively for flint glass.)
You are given a question and two statements. Idientify which of the statements is/are sufficient to answer the question. Question: In a city, some people travel to work by bus, some people travel to work by train, some people travel to work by both bus and train, and some travel to work neither by bus, nor by train. The number of people who travel to work by both bus and train is how much less than the number of people who travel to work by neither? Statements: (1) In the city, there are 384 people who travel to work by bus. (2) In the city, there are 672 people who travel to work by train,
A ray of light travels from a medium of refractive index m1 to a medium of refractive index m2. If “i” and “r” are the angle of incidence and refraction, then what is sin(i)/sin(r)?
If light travels in a medium of Refractive Index 1.4 through a distance 250 m in a given time interval, then how much distance will it cover in refractive index 1.75?
Consider the following statements.
1. A fibre is an optical system based upon the basic principle of total internal reflection.
2. In total internal reflection, the angle of incidence should always be greater than critical angle.
3. The critical angle is very low for a light ray coming from diamond to air.
Which of the statements given above is/are correct?
When light passes from air to glass it experience change in refractive index. and due to change in refractive index the wavelength of light changes and hence speed.
A GaAs optical source having a refractive index of 3.2 is coupled to a silica fiber having a refractive index of 1.42. Determine Fresnel reflection at interface in terms of percentage.
Out of total passengers of city 20% travels by bus, 50% of remaining travels by train, 30% of remaining travels by cab, rest 4200 passengers travels by metro. While taking health issue in account 25% of the total passengers decided to travel by foot. The number of passengers who opt to travel by foot?