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प्रश्न
Fig. shows a ray of white light that passes through a prism and produces a spectrum.
(a) Name the phenomenon that is taking place.
(b) What colour would you see at X and Y?
(c) What radiation would you detect above X and below Y?
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उत्तर
(a) Dispersion
(b) Red colour at X and violet colour at Y.
(c) Above X, we would detect infra-red radiation and below Y, ultra-violet radiation.
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संबंधित प्रश्न
A student very cautiously traces the path of a ray through a glass slab for different values of the angle of incidence (∠i). He then measures the corresponding values of the angle of refraction (∠r) and the angle of emergence (∠e) for every value of the angle of incidence. On analysing these measurements of angles, his conclusion would be
(A) ∠i > ∠r > ∠e
(B) ∠i = ∠e > ∠r
(C) ∠i < ∠r < ∠e
(D) ∠i = ∠e < ∠r
In the adjacent diagram, AO is a ray of light incident on a rectangular glass slab.
- Complete the path of the ray till it emerges out of the slab.
- In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles i and r?
- Mark angles of emergence by the letter e. How are the angles i and e related?
- Which two rays are parallel to each other? Name them.
- Indicate in the diagram the lateral displacement between the emergent ray and the incident ray. State one factor that affects the lateral displacement.
How does the deviation produced by a prism depend on the wavelength of incident light?
The critical angle for glass-air interface is :
Glass is transparent in nature. Why does glass powder look opaque? When water is poured over it, it again becomes transparent. Why?
State the factors on which the angle of deviation depends.
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 alongside a ray of light, PQ is incident normally on one face AB of an equilateral glass prism. What is the angle of incidence at the faces AB and AC?
Trace a ray of light incident at 30° on a surface if travelling from air to glass. What is the angle of refraction in this case? (R.I. for glass = 3/2).
Write the approximate values of speed of light in (i) air and (ii) glass. Use these values to calculate the refractive index of glass with respect to air.
