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प्रश्न
What is the cause of dispersion of light
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उत्तर
Cause of dispersion: Different colours of white light have different wavelengths. The wavelength of violet light is smaller than that of red light. The refractive index of a material in terms of the wavelength of the light is given by Cauchy’s expression.
`mu=a+b/lambda^2+c/lambda^4`
Here, a, b and c are constants for the material.
Thus, a material offers different refractive indices to lights of different wavelengths. This is the cause of dispersion of light
संबंधित प्रश्न
A ray PQ incident normally on the refracting face BA is refracted in the prism BAC made of material of refractive index 1.5. Complete the path of ray through the prism. From which face will the ray emerge? Justify your answer.
A ray of light passes through an equilateral glass prism such that the angle of incidence is equal to the angle of emergence and each of these angles is equal to 3/4 of angle of prism. Find the angle of deviation.
Describe an activity to show that the colours of white light splitted by a glass prism can be recombined to get white light by another identical glass prism. Also, draw a ray diagram to show the recombination of the spectrum of white light.
If three identical prisms are combined, is it possible to pass a beam that emerges undeviated? Undispersed?
The angular dispersion produced by a prism ___________ .
A prism can produce a minimum deviation δ in a light beam. If three such prisms are combined, the minimum deviation that can be produced in this beam is _______________.
The minimum deviations suffered by, yellow and violet beams passing through an equilateral transparent prism are 38.4°, 38.7° and 39.2° respectively. Calculate the dispersive power of the medium.
The refractive index of a material M1 changes by 0.014 and that of another material M2 changes by 0.024 as the colour of the light is changed from red to violet. Two thin prisms, one made of M1(A = 5.3°) and the other made of M2(A = 3.7°) are combined with their refracting angles oppositely directed. (a) Find the angular dispersion produced by the combination. (b) The prisms are now combined with their refracting angles similarly directed. Find the angular dispersion produced by the combination.
The refractive indices of material for red, violet and yellow colour light are 1.52, 1.62 and 1.59 respectively.
Calculate the dispersive power of the material. If the mean deviation is 40°. What will be the angular dispersion produced by a prism of this material?
What is meant by a thin prism?
