Advertisements
Advertisements
प्रश्न
Why do we get a spectrum of seven colors when white light is dispersed by a prism?
Advertisements
उत्तर
The refractive index of the material of the prism is different for different colours. White light is composed of seven colours. When white light is incident on a prism, the constituent colours get refracted through different angles and get dispersed. So, the rays of each colour emerge along different paths and become distinct. Hence, we get a spectrum of seven different colours.
APPEARS IN
संबंधित प्रश्न
When rays of light are incident on a glass slab then the incident ray and emergent ray are _________ each other.
- perpendicular
- parallel
- opposite
- concurrent
In your laboratory you trace the path of light rays through a glass slab for different values of angle of incidence (∠i) and in each case measure the values of the corresponding angle of refraction (∠r) and angle of emergence (∠e). On the basis of your observations your correct conclusion is:
(a) ∠i is more than ∠r, but nearly equal to ∠e
(b) ∠i is less then ∠r, but nearly equal to ∠e
(c) ∠i is more than ∠e, but nearly equal to ∠r
(d) ∠i is less than ∠e, but nearly equal to ∠r
Write a relationship between the angle of incidence and angle of refractions for a given pair of media
Name a prism required for obtaining a spectrum of Ultraviolet light.
Draw the diagram of refraction of light in the glass slab
A ray of light passes from glass into air. The angle of refraction will be:
(a) equal to the angle of incidence
(b) greater than the angle of incidence
(c) smaller than the angle of incidence
(d) 45°
Write the relation between the angle of incidence and the angle of refraction for a medium.
Draw diagrams to show the refraction of light from
- air to glass, and
- glass to air. In each diagram, label the incident ray, refracted ray, the angle of incidence
- and the angle of refraction (r).
Draw diagrams to show the refraction of light from glass to air. In diagram, label the incident ray, refracted ray, the angle of incidence (i) and the angle of refraction (r).
For which colour of white light, is the refractive index of a transparent medium the most?
With the help of diagram of the principal section of a prism, indicate its refracting surfaces, refracting edge and base.
How does the speed of light change when it passes from glass to water?
What do you understand by the statement the refractive index of glass is 1.5 for white light?
Fig 4.31 below shows a light ray of single colour incident normally on two prisms A and B. In each case draw the path of the ray of light as it enters and emerges out of the prism. Mark the angle wherever necessary.
A Water pond appears to be 2.7 m deep. If the refractive index of water is 4/3, find the actual depth of the pond.
Trace the path of a ray of light incident at an angle of 45° on a rectangular glass slab. Write the measure of the angle of refraction, the angle of emergence and the lateral displacement suffered by the ray as it passes through the slab.
Four students A, B, C and D traced the paths of incident ray and the emergent ray by fixing pins P and Q for incident ray and pins R and S for emergent ray for a ray of light passing through a glass slab.
The correct emergent ray was traced by the student:
(1) A
(2) B
(3) C
(4) D
-
- the angle of refraction and
- the angle of deviation for the ray?
A ray of light passes from air to water. In fig. 39, which of the ray A, B, C and D is the correct refracted ray?
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?
Light of a single colour is passed through a liquid having a piece of glass suspended in it. On changing the temperature of liquid, at a particular temperature, the glass piece is not seen.
Why is the light of a single colour used ?
How does the deviation produced by a prism depend on the wavelength of incident light?
Rewrite the following statement by selecting the correct option:
If a ray of light strikes a glass slab at an angle of 600 with the surface of the slab, the angle of incidence must be __________________.
Name the phenomenon responsible in the following case:
Apparent bending of a stick in water
Name the phenomenon responsible in the following case:
Twinkling of stars
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.
State the relation between the refractive index μ and the velocity of light (vm) in that medium.
How is the refractive index of a medium related to its real depth and apparent depth?
Express the refractive index μ of a medium in terms of the velocity of light.
Can the absolute refractive index of a medium be less than one?
How does the angle of deviation produced by a prism depend on the colour of light used? Which colour of white light is deviated (i) most, (ii) least, by a prism?
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.
(a) Does the light speed up or slow down in the glass,
(b) Give the reason for your answer.
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.
What should be the rate of the speed of light through the liquid to the speed through the glass so that there is no refraction of light at the boundaries of the glass block when the system is illuminated by the light of one colour?
Trace a ray of light incident at 30° on a surface if travelling from glass to air. What is the angle of refraction in this case? (R.I. for glass = 3/2).
Observe the figure and name the ray AB, ray CD, ray GH.
A ray of light strikes the surface of a rectangular glass slab such that the angle of incidence in air is
- 0°,
- 45°.
In each case, draw a diagram to show the path taken by the ray as it passes through the glass slab and emerges from it.
