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प्रश्न
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उत्तर
Critical angle: The angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90o.
Total internal reflection: It is an optical phenomenon that occurs when a ray of light strikes the boundary of denser medium at an angle greater than the critical angle w.r.t. the normal of the surface; this ray is then totally reflected back into the denser medium.
The two necessary conditions for total internal reflection to take place are:
1.The light ray must proceed from denser to rarer medium.
2. Angle of incidence in denser medium should be greater than the critical angle for the pair of media in contact.
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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.
Total internal reflection occurs only when a ray of light passes from a ______ medium to a ______ medium.
The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. [Write necessary angles].
Plot a graph between
Sine of angle of incidence versus sine of angle of refraction,
Express the refractive index μ of a medium in terms of the angle of incidence i in air and the angle of refraction r in a denser medium.
What is meant by the term ‘critical angle’?
Explain ‘mirage’ as an illustration of refraction.
A bundle of glass threads, each of which is capable of transmitting messages using light waves is called ______.
The critical angle is defined as the angle of incidence at which the total internal reflection starts to occur.
- Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-cladding interface.
- Reason (R): Refractive index of the material of the cladding of the optical fibre is greater than that of the core.
