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Question
Make two diagrams to explain refraction and dispersion.
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Solution
When we see a pool of water. The pool appears less deep as it is. This is due to the refraction of light.
When white light is allowed to pass through the glass prism. It splits into seven colour this is called dispersion of light.
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RELATED QUESTIONS
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.
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.
As light rays emerge from a glass prism into air, are they refracted towards or away from the normal?
What will happen if another similar glass prism is placed upside down behind the first prism?
Describe how you could demonstrate that white light is composed of a number of colours.
Which of the following colour of white light has the least wavelength?
(a) red
(b) orange
(c) violet
(d) blue
Out of the following, the colour of light having the maximum wavelength is:
(a) violet
(b) indigo
(c) green
(d) orange
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.
Make the correct choice for each of the following:
Which one of the following Fig correctly shows the path of the ray through the glass block?
Write three conditions necessary to obtain a pure spectrum on a screen. Name the instrument in which the conditions stated by you are fulfilled.
Suggest one way, in each case, by which we can detect the presence of Infrared radiations.
The periscope is an optical device with a polished surface that reflects the light falling on it.
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.
What is a rainbow?
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:
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.
Which colour will show the maximum angle of deviation and which colour will show the minimum angle of deviation?
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.
