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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
Draw a ray diagram to show the dispersion of white light.
In the formation of spectrum of white light by a prism:
which colour is deviated most?
The coloured light having the maximum speed in glass prism is:
(a) blue
(b) green
(c) violet
(d) yellow
Which of the following colour of white light has the least wavelength?
(a) red
(b) orange
(c) violet
(d) blue
Why do you not see a spectrum of colours when light passes through a flat pane of glass?
The splitting of white light into its constituent colours is called .............
A ray of white light falls on a prism. Draw a ray diagram to show that the prism disperses the white light.
In figure AO is the ray of white light falling on a prism PQR. Complete the diagram till the light emerges out from the prism and falls on the screen.
Complete the ray diagram given below to show the nature of light produced on the screen.
While performing the experiment to trace the path of a ray of light passing through a glass prism, four students marked the incident ray and the emergent ray in their diagrams in the manner shown below. 
(A) I
(B) II
(C) III
(D) IV
Refer to fig
(i) Name the lens L.
(ii) What are the points O, O' called?
(iii) Complete the diagram to form the image of the object AB.
(iv) Write three characteristics of the image.
An object AB is placed in front of a convex lens as shown in fig. 4. Complete the ray diagram and obtain the image formed and state the nature of the image.
How can the presence of ultraviolet radiation be detected?
Match the Columns:
| Column ‘A’ | Column ‘B’ |
| The wavelength of red light | (a) 600 nm |
| (b) 700 nm | |
| (c) 500 nm |
Observe the given figure and answer the following questions.
- Which colour light rays bend most?
- Which colour light rays bend least.
- What is the wavelength of violet light rays?
Which of the following is a natural phenomenon which is caused by the dispersion of sunlight in the sky?
State the correct sequence (1-7) of colours in the spectrum formed by the prisms A and B, shown in the following figure.
The angle of deviation through a prism is minimum when
- Incident rays and emergent rays are symmetric to the prism.
- The refracted ray inside the prism becomes parallel to its base.
- The angle of incidence is equal to that of the angle of emergence.
- When the angle of emergence has doubled the angle of incidence.
Choose the correct answer from the options given below:
dispersive power of crown glass? Given that µv = 1.5230, µr = 1.5145
Make a rainbow
Try to make your own rainbow. You can try this project in the morning or in the evening. Stand with your back towards the Sun. Take a hosepipe or a water pipe used in the garden. Make a fine spray in front of you. You can see different colours of rainbow in the spray.
