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प्रश्न
Total internal reflection can take place only if ______.
पर्याय
light goes from an optically rarer medium (smaller refractive index) to optically denser medium
light goes from optically denser medium to rarer
mediumthe refractive indices of the two media are close to each other
the refractive indices of the two media are widely different.
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उत्तर
Total internal reflection can take place only if the light goes from an optically denser medium to a rarer medium.
Explanation:
The angle of incidence is greater than the critical angle.
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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.
State the relation between the critical angle and the absolute refractive index of a medium.
A light ray does not bend at the boundary in passing from one medium to the other medium if the angle of incident is ______.
Name two factors which affect the critical angle for a given pair of media. State how do the factors affect it.
Write the relation between the refractive index and critical angle for a given pair of optical media?
Swarali has got the following observations while doing an experiment. Answer her questions with the help of observations.
Swarali observed that the light bent away from the normal, while travelling from dense medium to rarer medium. When Swarali increased the values of angle of incidence (i), the values of angle of refraction (r) went on increasing. But at a certain angle of incidence, the light rays returned into the dense medium.
So, Swarali has some questions. Answer them –
a) Name this certain value of ‘i ’. What is the value of ‘r’ at that time ?
b) Name this process of returning of light in dense medium. Explain the process.
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.
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].
If a light ray does not undergo, refraction at the boundary between two media, the angle of incidence is:
Write down the relationship between the critical angle and the refractive index of the medium.
Images formed by totally reflecting prisms are brighter than the image formed by ordinary reflected light, why?
A ray of light incident at an angle of incidence ‘i’ passes through an equilateral glass prism such that the refracted ray inside the prism is parallel to its base and emerges from the prism at an angle of emergence ‘e’.
What can you say about the value of the angle of deviation in such a situation?
State one factor on which a critical angle for a given pair of media depends. The critical angle for the glass-air interface is 45° for the yellow light. Will it be equal to, less than or greater than 45° for (i) red light, (ii) blue light?
Name the factors affecting the critical angle for the pair of media.
Explain ‘mirage’ as an illustration of refraction.
For the same angle of incidence, the angle of refraction in four media A, B, C and D are 25°, 30°, 35° and 40° respectively. The speed of light is least in medium ______.
For a ray of light, the critical angle is minimum when it travels from ______.
The twinkling effect of star light is due to ______.
The critical angle is defined as the angle of incidence at which the total internal reflection starts to occur.
When a ray of light is refracted from one medium to another, then the wavelength changes from 6000 Å to 4000 Å. The critical angle for the interface will be ______.
