Advertisements
Advertisements
Questions
How does the deviation produced by a triangular prism depend on the colour (or wavelength) of light incident on it?
Advertisements
Solution 1
Light of different colours have different speeds in a medium.
Therefore, the refractive index of glass (the material of prism) is different for different colours of light and the deviation caused by a prism is different for different colours of light.
Violet is deviated the most because in glass, speed of violet is least.
Red is deviated the least because in glass, speed of red is most.
Solution 2
Because different colours have different wavelengths in the medium, the deviation that a prism produces depends on the colour (or wavelengths) of the light that impinges on it. Consequently, for various colours of light, the refractive index of glass (the prism's substance) differs, and the deviation brought about by the prism varies accordingly.
APPEARS IN
RELATED QUESTIONS
In following diagram shows a thin beam of white light from a source S striking on one face of a prism.
A slit is placed in between the prism and the screen to pass only the light of green colour. What will you then observe on the screen?
In following diagram shows a thin beam of white light from a source S striking on one face of a prism.
What conclusion do you draw from the observation in part (b) above?
(i) Draw a diagram to show the splitting of white light by a prism into its constituent colour.
(ii) Draw another diagram to show how the colours of spectrum of white light can be combined
to give the effect of white light.
Draw another diagram to show how the colours of spectrum of white light can be combined to give the effect of white light.
Fig shows part of the arrangement for obtaining pure spectrum.
(a) Complete thediagram and show how to obtain a pure spectrum.
(b) What are the conditions necessary for obtaining a pure spectrum?
Give a reason, why the violet colour of white light deviated most and red colour of white light deviated least.
Name the radiation of a wavelength longer than 8 × 10−7 m.
Draw a neat diagram to show the arrangement you would use to project a pure spectrum of white light on a screen.
Comment on the statement: ‘When any ray of white light is incident on a glass prism, it simply disperses it into its seven constituent colours.
The wavelengths for the light of red and blue colours are nearly 7·8 × 10-7 m and 4·8 × 10-7 m respectively.
Which colour has greater speed in glass?
