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प्रश्न
What is meant by the term ‘critical angle’?
What is a critical angle?
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उत्तर
It is the angle of incidence in the denser medium corresponding to which the angle of refraction in the rarer medium is 90°.
संबंधित प्रश्न
You are given prisms made of crown glass and flint glass with a wide variety of angles. Suggest a combination of prisms which will
(a) deviate a pencil of white light without much dispersion,
(b) disperse (and displace) a pencil of white light without much deviation.
State the conditions required for total internal reflection of light to take place
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.
Draw the diagram of a right-angled isosceles prism which is used to make an invented image erect.
In the given figure PQ and PR are the two light rays emerging from an object P. The ray PQ is refracted as QS.
- State the special name given to the angle of incidence ∠PQN of the ray PQ.
- What is the angle of refraction for the refracted ray QS?
- Name the phenomenon that occurs if the angle of incidence ∠PQN is increased.
- The ray PR suffers partial reflection and refraction on the water-air surface. Give reason.
- Draw in the diagram the refracted ray for the incident ray PR and hence show the position of image of the object P by the letter P’ when seen vertically from above.
Write the relation between the refractive index and critical angle for a given pair of optical media?
Total internal reflection can take place only if ______.
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
Define critical angle for a given medium.
Choose the correct option.
Consider the following phenomena/ applications: P) Mirage, Q) rainbow, R) Optical fibre and S) glittering of a diamond. Total internal reflection is involved in
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?
Answer the following question.
What are the advantages of optical fibre communication over electronic communication?
Total internal reflection can take place only if light is travelling from ______.
The critical angle is defined as the angle of incidence at which the total internal reflection starts to occur.
What is a mirage? How does it occur?
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.
Small air bubbles rising up a fish tank appear silvery when viewed from some particular angle is due to the ______.
