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प्रश्न
The critical angle for glass-air is 45° for the light of yellow colour. State whether it will be less than, equal to, or more than 45° for (i) ref light, (ii) blue light?
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उत्तर
As the wavelength decreases (or increases) refractive index becomes more (or less) and critical angle becomes less (or more).
(i) For red light the critical angle will be more than 45° and
(ii) For blue light the critical angle will be less than 45°.
संबंधित प्रश्न
Write a short note on dispersion of light.
After tracing the path of a ray of light passing through a rectangular glass slab for four different values of the angle of incidence, a student reported his observations in tabular form as given below:
| S.No | ∠ i | ∠ r | ∠ e |
| I | 30° | 19° | 29° |
| II | 40° | 28° | 40° |
| III | 50° | 36° | 50° |
| IV | 60° | 40° | 59° |
The best observation is
(A) I
(B) II
(C) III
(D) IV
Why do we get a spectrum of seven colors when white light is dispersed by a prism?
Which colour of light travels fastest in any medium except air?
For which colour of white light, is the refractive index of a transparent medium the most?
A ray of light is passing from a transparent medium 1 to another transparent medium 2 (i) Speed up (ii) slows down. In each case, state whether the refractive index of medium 2 is equal to, less than or greater than the refractive index of medium 1.
An object is viewed through a glass prism with its vertex pointing upwards. It appears to be displaced upward. Explain the reason.
Name the phenomenon responsible in the following case:
Apparent bending of a stick in water
The refractive index of air with respect to glass is defined: as gµa = sin i/sin r
Write down a similar expression for aµg in terms of angle i and r.
In the diagram below, PQ is a ray of light incident on a rectangular glass block.
Copy the diagram and complete the path of the ray of light through the glass block. In your diagram, mark the angle of incidence by letter ‘i’ and the angle of emergence by the letter ‘e’.
