Advertisements
Advertisements
Question
Why do you not see a spectrum of colours when light passes through a flat pane of glass?
Advertisements
Solution
When light passes through a flat pane of glass, the refracted light emerges out of the glass pane without any deviation because a glass pane has two sides that are parallel to each other. As the emergent light does not deviate from the original direction by any angle, we do not see the different colours of the light separated out in the form of a spectrum. Therefore, in order to view a spectrum of colours, the incident rays have to fall on an object whose surfaces are not parallel, such as a glass prism (triangular shape).
APPEARS IN
RELATED QUESTIONS
In the following ray diagram the correctly marked angle are:
(a) ∠i and ∠e
(b) ∠A and ∠D
(c) ∠i, ∠e and ∠D
(d) ∠r, ∠A and ∠D
In the formation of spectrum of white light by a prism:
which colour is deviated most?
A beam of white light is shone onto a glass prism. The light cannot be:
(a) deviated
(b) dispersed
(c) focused
(d) refracted
Which of the following colour of white light is least deviated by the prism?
(a) green
(b) violet
(c) indigo
(d) yellow
The splitting up of white light into seven colours on passing through a glass prism is called:
(a) refraction
(b) deflection
(c) dispersion
(d) scattering
How does the speed of light determine the optical density of a medium?
Out of air and glass, which is optically rarer? Give reason.
The diagram below shows the path taken by a narrow beam of yellow monochromatic light passing through an equiangular glass prism. If the yellow light is replaced by a narrow beam of white light incident at the same angle, draw another diagram to show the passage of white light through the prism and label it to show the effect of prism on the white light.
- A beam of monochromatic light undergoes minimum deviation through an equiangular prism, how does the beam pass through the prism, with respect to its base?
- If white light is used in the same way as in part (a) above, what change do you expect in the emergent beam?
- What conclusion do you draw about the nature of white light in part (b)?
Complete the ray diagram given below to show the nature of light produced on the screen.
What is the cause of the dispersion of white light through a glass prism? Draw a ray diagram to show the path of light when two identical glass prisms are arranged together in an inverted position with respect to each other and a narrow beam of white light is allowed to fall obliquely on one of the faces of the prisms.
Distinguish between an impure spectrum and a pure spectrum.
Write the range of wavelength of the infrared spectrum.
Say TRUE or FALSE
Rainbow is formed by dispersion of which light by water drops
Say TRUE or FALSE
After passing through a prism, white light splits into a band of seven colours
What is dispersion? Explain in detail.
During dispersion of white light by prism placed in air, for a particular value of angle of prism,
A prism of refractive index `sqrt2` and refracting angle A produces minimum deviation δm of a ray on one face at an angle of incidence 45°, The values of A and δm are, respectively ______.
