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
Explain how the formation of a rainbow occurs.
Name a prism required for obtaining a spectrum of Ultraviolet light.
How can you bend light away from the normal?
When light travels from a rarer to a denser medium, its speed ______.
How does the angle of minimum deviation produces by a prism change with increase in :
the wavelength of incident light
The diagram alongside shows the refraction of a ray of light from air to a liquid.
- Write the values of (i) angle of incidence, (ii) angle of refraction.
- Use Snell’s law to find the refractive index of liquid with respect to air.

A total reflecting right angled isosceles prism can be used to deviate a ray of light through:
(a) 30° (b) 60° (c) 75° (d) 90°.
Select from the following the best set-up for tracing the path of a ray of light through a rectangular glass slab:

(A) I
(B) II
(C) III
(D) IV
Fig shows a lens as a combination of a glass block and two prisms.

(i) Name the lens formed by the combination.
(ii) what is the XX' called?
(iii) Complete the ray diagram and show the path of the incident ray PQ after passing through the lens.
(iv) The final emergent ray will either meet XX' at a point or appear to come from a point on XX'. what is the point called?
Draw a ray diagram showing the lateral displacement of a ray of light when it passes through a parallel sided glass slab.
What is meant by the refraction of light?
Why do the faces of persons sitting around campfire appear to shimmer?
Why is the colour red used as a sign of danger?
Express the refractive index μ of a medium in terms of the velocity of light.
Complete the ray diagram showing its emergence into the air after passing through the prism.

The velocity of light in diamond is 121000 kms-1. What is its refractive index?
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.
