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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
Figure shows a ray of light passing through a prism. If the refracted ray QR is parallel to the base BC, show that (i) r1 = r2 = A/2 and (ii) angle of minimum deviation, Dm = 2i − A.
Can the dispersive power \[\omega = \frac{\mu_u - \mu_r}{\mu - 1}\] be negative? What is the sign of ω if a hollow prism is immersed into water?
If three identical prisms are combined, is it possible to pass a beam that emerges undeviated? Undispersed?
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 _______________.
By properly combining two prisms made of different materials, it is possible to
(a) have dispersion without average deviation
(b) have deviation without dispersion
(c) have both dispersion and average deviation
(d) have neither dispersion nor average deviation
A thin prism of crown glass (μr = 1.515, μv = 1.525) and a thin prism of flint glass (μr = 1.612, μv = 1.632) are placed in contact with each other. Their refracting angles are 5.0° each and are similarly directed. Calculate the angular dispersion produced by the combination.
In a regular prism, what is the relation between angle of incidence and angle of emergence when it is in the minimum deviation position?
Calculate dispersive power of a transparent material given : nv = 1.56, nr = 1.54, ny = 1.55.
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?
