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प्रश्न
What is refraction of light?
What is refraction of light? Explain with the help of an example.
Explain the refraction of light.
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उत्तर
- Light changes its direction when going from one transparent medium to another transparent medium. This change in direction is called the refraction of light.
- For example, the coin appears to disappear in a vessel when viewed from a specific angle. But as soon as the water is poured into the vessel at a certain level, the coin appears. This phenomenon is because light rays coming from the coin emerge out of the water and change their direction due to the refraction of light.
संबंधित प्रश्न
| Column I | Column II | Column III | |
| 1 | Dispersion | Long-sightedness | Twinkling of stars |
| 2 | Refraction | Splitting of white light into component colours | Convex lens |
| 3 | Hypermetropia | Change in the direction of the ray of light due to change in medium | Spectrum of seven colours |
Name the phenomenon responsible for the following effect:
When we sit in front of a plane mirror and write with our right hand, it appears in the mirror that we are writing with the left hand.
A boy with a mouth 5 cm wide stands 2 m away from a plane mirror. Where is his image and how wide is the image of his mouth?
State the uses of plane mirrors.
What is meant by 'reflection of light'?
The image in a plane mirror is virtual and laterally inverted. What does this statement mean?
Write all the capital letters of the alphabet which look the same in a plane mirror.
The image formed by a plane mirror is :
(a) virtual, behind the mirror and enlarged.
(b) virtual, behind the mirror and of the same size as the object.
(c) real, at the surface of the mirror and enlarged.
(d) real, behind the mirror and of the same size as the object.
The figure given alongside shows the image of a clock as seen in a plane mirror. The correct time is:
A man stands 10 m in front of a large plane mirror. How far must the walk before he is 5 m away from his image?
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?
A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is ______.
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 goes from water into air. Will it bend towards the normal or away from the normal?
A ray of light travelling in air is incident on a rectangular glass block and emerges out into the air from the opposite face. Draw a labelled ray diagram to show the completer path of this ray of light. Mark the two points where the refraction of light takes place. What can you say about the final direction of ray of light?
Light travels more quickly through water than through glass.
- Which is optically denser: water or glass?
- If a ray of light passes from glass into water, which way will it bend: towards the normal or away from the normal?
With the help of a labelled diagram, explain why a tank full of water appears less deep than it actually is.
- With the help of a diagram, show how when light falls obliquely on the side of a rectangular glass slab, the emergent ray is parallel to the incident ray.
- Show the lateral displacement of the ray on the diagram.
Show the lateral displacement of the ray on the diagram.
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
A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of:
(a) 0°
(b) 45°
(c) 90°
(d) 120°
The depth of a pond when seen from above appears to be less.
Water is optically .......... than air.
When a ray of light travels from water to air, it bends ............. the normal.
When a ray of light travels from air to glass, it bends .......... the normal.
What do you understand by refraction of light?
What is the cause of refraction of light when it passes from one medium to another?
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.
A ray of light passes from medium 1 to medium 2. Which of the following quantities of the refracted ray will differ from that of the incident ray: Speed, intensity, frequency, wavelength?
A small air bubble in a glass block when seen from above appears to be raised because of ______.
The size of image of an object by a convex lens of focal length 20 cm is observed to be reduced to `1/3` rd of its size . Find the distance of the object from the optical centre of the lens .
List in proper sequence the steps of the experiment for determining the approximate focal length of a given concave mirror by obtaining the image of a distant object.
The phenomenon of change in the direction of light when it passes from one transparent medium to another is called ___________.
Identify the wrong figure from the following.
The incident rays and refracting rays are on opposite sides of the normal.
Write scientific reason.
A pencil appears to be broken near the surface of water.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
The refractive index of four substances A, B, C, and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in
The deviation of light ray from its path when it travels from one transparent medium to another transparent medium is called ______.
If a beam of red light and a beam of violet light are incident at the same angle on the inclined surface of a prism from air medium and produce angles of refraction r and v respectively, which of the following is correct?
The angle of incidence from air to glass at the point O on the hemispherical glass slab is.
Light is refracted or bent while going from one medium to another because of its ______ changes.
Which is optically denser out of the two medium M1& M2 having the refractive indices = 1.71 and 1.36 respectively?
In refraction of light through a glass slab, the directions of the incident ray and the refracted ray are ______.
