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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
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 two conditions necessary for total internal reflection to occur.
Total internal reflection occurs only when a ray of light passes from a ______ medium to a ______ medium.
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.
Define critical angle for a given medium.
In the following figure, show two rays A and B travelling from water to air. If the critical angle for water- air surface is 48°, complete the ray diagram showing the refracted rays for each. State conditions when the ray will suffer total internal reflection.
How does a ray of light bend when it travels from rarer to denser medium
Choose the correct option.
Angles of deviation for extreme colours are given for different prisms. Select the one having maximum dispersive power of its material.
Answer the following question.
Under what conditions are total internal reflection possible? Explain it with a suitable example.
Answer the following question.
Why is prism binoculars preferred over traditional binoculars? Describe its working in brief.
Solve Numerical example.
From the given data set, determine angular dispersion by the prism and dispersive power of its material for extreme colours. nR = 1.62 nV = 1.66, δR = 3.1°
Observe the given figure and write appropriate phenomenon of light in the box.
A green light is incident from the water to the air-water interface at the critical angle (C). Select the correct statement.
What are the conditions to achieve total internal reflection?
A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5° and the prism is made of a material of refractive index 1.5, the angle of incidence is ______.
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.
Which of the following is used in optical fibres?
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 ______.
