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प्रश्न
When a beam of white light is passed through a prism, it splits to form lights of seven colours. Is it possible to recombine the lights of seven colours to obtain the white light again? Explain your answer.
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उत्तर
When a beam of white light is passed through a prism, it splits to form lights of seven colours. It is possible to recombine the lights of seven colours to obtain white light again.
Recombination of colours to form white light again is possible if a second glass prism is placed upside down behind the first prism. A patch of white light is obtained on a screen placed behind the second prism because the refraction produced by the second prism is equal and opposite to the refraction produced by the first prism.
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संबंधित प्रश्न
The path of a ray of light passing through a glass prism is shown below:

In this diagram, the angle of prism, angle of incidence, angle of emergence and angle of deviation, respectively, have been represented by:
(A) O, Y, Z and N,
(B) P, Y, M and Z,
(C) O, X, M and Z,
(D) P, X, Z and N.
State the cause of dispersion of white light
Make two diagrams to explain refraction and dispersion.
Which is refracted most by a prism : red light or violet light? Explain why?
The colour of white light which is deviated the maximum on passing through the glass prism is:
(a) blue
(b) indigo
(c) red
(d) orange
When white light passes through a prism, it ............
The speed of light in air or vacuum is
A ray of light moving from an optically rarer to a denser medium
You are given a disc divided into seven sectors with colours violet, indigo, blue, green, yellow, orange and red in them. What would be its colour when it is rotated rapidly?
A glass prism is able to produce the spectrum when white light passes through it, but a glass slab doesn’t produce any spectrum. Explain why it is so.
If a monochromatic beam of light undergoes minimum deviation through an equiangular prism, how does the beam pass through the prism, with respect to its base?
Complete the ray diagram given below to show the nature of light produced on the screen.
The completed ray diagram is as shown below:

A student has to trace the path of a ray of light through a glass prism. List four precautions he should observe for better results.
Write three conditions necessary to obtain a pure spectrum on a screen. Name the instrument in which the conditions stated by you are fulfilled.
In the figure, a beam of light consisting of three colours blue, red, and yellow is incident on a prism and on a rectangular glass block respectively. Complete the diagram by drawings of the refracted and emergent rays.

The phenomena of light involved in the formation of rainbow are ______.
State the correct sequence (1-7) of colours in the spectrum formed by the prisms A and B, shown in the following figure.

The periscope is an optical device with a polished surface that reflects the light falling on it.
Observe the given diagram and answer the questions:

- Name the process shown in the figure.
- Name the colour that deviates the most.
- Name the colour that deviates the least.
- Name any one phenomenon in nature which is based on the above process.
- Define ‘spectrum’.
When sunlight passes through water droplets in the atmosphere it gets dispersed into its constituent colours forming a rainbow. A similar phenomenon is observed when white light passes through a prism.
Which colour will show the maximum angle of deviation and which colour will show the minimum angle of deviation?
