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Question
Describe an activity to show that colours of white light splitted by a glass prism can be recombined to get white light by another identical glass prism. Also draw ray diagram to show the recombination of the spectrum of white light.
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Solution
The seven colours of a spectrum can be recombined to give back white light as
- Two identical glass prisms are placed such that their refracting surfaces are in opposite direction (placed inverted). When a beam of light is allowed to fall on the surface of one prism, a patch of ordinary white light is obtained on a screen placed behind the second prism.
- The first prism disperses the white light into seven coloured rays. The second prism receives all the seven coloured rays from the first prism and recombines them into original white light. This is because the refraction produced by the second prism is equal and opposite to that produced by the first prism. Hence, the light coming out of the second prism will be white

RELATED QUESTIONS
Study the following figure in which a student has marked the angle of incidence (∠i), angle of refraction (∠r), angle of emergence (∠e), angle of prism (∠A) and the angle of deviation (∠D). The correctly marked angles are

(a) ∠A and ∠i
(b) ∠A, ∠i and ∠r
(c) ∠A, ∠i, ∠e and ∠D
(d) ∠A, ∠i, ∠r and ∠D
Study the following ray diagram:

In this diagram, the angle of incidence, the angle of emergence and the angle of deviation respectively have been represented by
(A) y, p, z
(B) x, q, z
(C) p, y, z
(D) p, z, y
What do you understand by the term spectrum?
Write the range of wavelength of the ultraviolet spectrum.
The splitting of white light in to seven colors is called ______.
The phenomena of light involved in the formation of rainbow are ______.
In dispersion, the color of light that will bend more is ______.
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 ______.
State True or False:
"Wavelength of red light is close to 700 nm.”
State the colour which bends:
- The most.
- The least while passing through a glass prism.
