Advertisements
Advertisements
Question
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.
Advertisements
Solution
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.
APPEARS IN
RELATED QUESTIONS
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.
State the cause of dispersion of white light passing through a glass prism. How did Newton show that white light of sun contains seven colours using two identical glass prisms. Draw a ray diagram to show the path of light when two identical glass prisms are arranged together in inverted position with respect to each other and a narrow beam of white light is allowed to fall obliquely on one of the focus of the first prism.
Define the term dispersion of white light.
Fill in the blank with suitable word:
When a ray of light enters a prism, it bends ................ the normal ; as it leaves the prism, it bends ................. the normal.
What will happen if another similar glass prism is placed upside down behind the first prism?
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
The splitting of white light into its constituent colours is called .............
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?
What conclusion do you draw about the nature of white light in part (b)?
In an experiment to trace the path of a ray of light through a triangular glass prism, a student would observe that the emergent ray
(a) is parallel to the incident ray.
(b) is along the same direction of incident ray.
(c) gets deviated and bends towards the thinner part of the prism.
(d) gets deviated and bends towards the thicker part (base) of the prism.
If white light is used in same way what change is expected in the emergent beam?
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 the range of wavelength of the visible spectrum.
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 write appropriate phenomenon of light in the box.
Assertion: We can see the rainbow in the sky when the rain starts falling after a spell of bright sunlight.
Reason: The rainbow is formed due to the dispersion of light.
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 ______.
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.
Instead of sunlight, a green-coloured ray is passed through a glass prism. What will be the colour of the emergent ray?
