Advertisements
Advertisements
Question
Explain how the formation of a rainbow occurs.
Solution
- The beautiful phenomenon of the rainbow is a combination of different phenomena – dispersion, refraction, and reflection of light.
- The rainbow appears in the sky after a rain shower.
- The water droplets act as small prisms.
- When sunlight enters the water droplets present in the atmosphere, they refract and disperse the incident sunlight.
-
Then they reflect it internally inside the droplet and finally again refract it.
- As a collective effect of all these phenomena, the seven coloured rainbows are observed.
APPEARS IN
RELATED QUESTIONS
Which property of light makes a pencil cast a shadow when it is held in front of a light source?
A ray of light strikes a plane mirror such that its angle of incidence is 30°. What angle does the reflected ray make with the mirror surface?
The letter F is placed in front of a plane mirror:
How would its image look like when seen in a plane mirror?
What is lateral inversion? Explain by giving a suitable example.
What are the important differences between looking at a photograph of your face and looking at yourself in a plane mirror?
What type of reflection of light takes place from a cinema screen?
A man sits in an optician's chair looking into plane mirror which is 2 m away from him and views the image of a chart which faces the mirror and is 50 cm behind his head. How far away from his eyes does the chart appear to be?
If a ray of light goes from a rarer medium to a denser medium, will it bend towards the normal or away from it?
A ray of light passes from air into a block of glass. Does it bend towards the normal or away from it?
Fill in the following blank with suitable word:
Light bends when is passes from water into air. We say that it is ............
What is meant by 'refraction of light'? Draw a labelled ray diagram to show the refraction of light.
What is meant by the 'angle of incidence' and the 'angle of refraction' for a ray of light?
Light travels more quickly through water than through glass.
If a ray of light passes from glass into water, which way will it bend : towards the normal or away from the normal?
A coin in a glass tumbler appears to rise as the glass tumbler is slowly filled with water. Name the phenomenon responsible for this effect.
State two factors on which the lateral displacement of the emergent ray depends.
When a ray of light travelling in glass enters into water obliquely:
(a) it is refracted towards the normal
(b) it is not refracted at all
(c) it goes along the normal
(d) it is refracted away from the normal
Image is formed by a mirror due to refraction of light.
Water is optically .......... than air.
Air is optically .......... than glass.
Draw suitable diagrams to illustrate how a beam of light incident parallel to the principal axis is reflected by:
(a) a concave mirror, and (b) a convex mirror
The diagram (figure) given below shows two parallel rays 1 and 2 incident on (a) a concave mirror, (b) a convex mirror. Draw the reflected rays and mark the focus by the symbol F.
A light ray suffers reflection and refraction at the boundary in passing from air to water. Draw a neat labelled ray diagram to show it.
Fill in the blank and Explain the completed sentences.
The change in ______ of light rays while going from one medium to another is called refraction.
Due to _______ pencil looks bent in water, in the given experiment.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
The speed of light varies in different media.
Write scientific reason.
The bottom of a pond appears raised.
Explain the working of a periscope.
A ray of light traveling in medium 1 strikes and travels into another transparent medium 2. If the speed of light is greater in medium 1, the ray will ______.
The ratio of the sine of the angle of incidence to the sine of ______ is constant.
A water tank appears shallower when it is viewed from the top due to refraction.
Twinkling of stars and Mirage are the two phenomena occurring due to refraction.
Which is optically denser out of the two medium M1& M2 having the refractive indices = 1.71 and 1.36 respectively?
Match the following:
| Column I | Column II | ||
| 1. | r > 90 | a. | Light gazes at the surface of separation between the two modes. |
| 2. | r = 90 | b. | No refraction. |
| 3. | r < 90 | c. | Refracted ray away from the normal |
In refraction of light through a glass slab, the directions of the incident ray and the refracted ray are ______.
