Advertisements
Advertisements
प्रश्न
What is total internal reflection?
Explain total internal reflection of light.
Advertisements
उत्तर
Total internal reflection is the phenomenon when a ray of light travelling in a denser medium is incident at the surface of a rarer medium such that the angle of incidence is greater than the critical angle for the pair of media, and the ray is totally reflected back into the denser medium.
APPEARS IN
संबंधित प्रश्न
The diagram below shows a point source P inside a water container. Four rays A, B, C, D starting from the source P are shown up to the water surface
1) Show in the diagram the path of these rays after striking the water surface.
The Critical Angle for the water-air surface is 48°.
2) Name the phenomenon which the rays B and D exhibit.
Name the factors affecting the critical angle for the pair of media.
State the relation between the critical angle and the absolute refractive index of a medium.
Calculate the speed of light in a medium whose critical angle is 30° ?
The observation made by Swarali while doing the experiment is given below. Based on these write answers to the questions:
Swarali found that the light ray travelling from the denser medium to rarer medium goes away from the normal. If the angle of incidence (i) is raised by Swarali, the angle of refraction (r) went on increasing. However, after certain value of the angle of incidence the light ray is seen to return back into the denser medium.
Questions:
- What is the specific value of∠i called?
- What is the process of reflection of incident rays into denser medium called?
- Draw the diagrams of three observations made by Swarali.
Define critical angle for a given medium.
(a) A ray of monochromatic light enters glass PQRS as shown in the fig. Complete the path of ray till it emerges from the glass. (Critical angle of glass is 420).
(b) Draw diagram of a prism periscope.
(c) What are the advantages of total internal reflecting prism over plane mirror?
What is meant by the statement, ‘the critical angle for diamond is 24°’?
A ray of light passes through a right-angled prism as shown in the figure. State the angles of incidence at the faces AC and BC.
The adjacent diagram shows two right-angled isosceles prisms A and B. Complete the diagram to show the path of rays P and Q emerging out of the prism B. What principles have you used to complete the diagram?
A spherical marble, of refractive index 1.5 and curvature 1.5 cm, contains a tiny air bubble at its centre. Where will it appear when seen from outside?
Explain ‘mirage’ as an illustration of refraction.
Answer the following question.
What are the advantages of optical fibre communication over electronic communication?
Solve Numerical example.
A monochromatic ray of light is incident at 37° on an equilateral prism of refractive index 3/2. Determine angle of emergence and angle of deviation. If angle of prism is adjustable, what should its value be for emergent rays to be just possible for the same angle of incidence?
Total internal reflection can take place only if light is travelling from ______.
A bundle of glass threads, each of which is capable of transmitting messages using light waves is called ______.
What is the phenomenon used in optical fiber? Explain.
A jar of height h is filled with a transparent liquid of refractive index µ (Figure). At the centre of the jar on the bottom surface is a dot. Find the minimum diameter of a disc, such that when placed on the top surface symmetrically about the centre, the dot is invisible.
A light is entering from one medium refractive index `("RI" =5/3)` to another medium at an angle 30°. The angle of refraction for other medium is sin-1 `(5/6)`. then the increase in angle of incidence is ______ such that the ray of light reflected back into the same medium.
