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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
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 the name of the phenomenon involved?
What type of reflection of light takes place from a cinema screen?
The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?
State the uses of plane mirrors.
Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram:
- Incident ray
- Point of incidence
- Normal
- Reflected ray
- Angle of incidence
- Angle of reflection
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.
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 ______.
Explain how to read the following message which was found on some blotting paper:
State two effects caused by the refraction of light.
As light rays pass from water into glass, are they refracted towards the normal or away from the normal?
Which phenomenon of light makes the water to appear shallower than it really is?
Fill in the following blank with suitable word:
Light bends when is passes from water into air. We say that it is ............
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?
With the help of a labelled diagram, explain why a tank full of water appears less deep than it actually is.
Name the phenomenon due to which a pencil partly immersed in water and held obliquely appears to be bent at the water surface.
When a ray of light travelling in glass enters into water obliquely ______.
How does the light have to enter the glass:
to produce a large amount of bending?
A ray of light when passes from glass to air, bends towards the normal.
Image is formed by a mirror due to refraction of light.
Air is optically .......... than glass.
When a ray of light travels from air to glass, it bends .......... the normal.
What do you understand by refraction of light?
Draw a diagram showing the refraction of a light ray from water to glass. Label on it the incident ray, the angle of incidence (/), and the angle of refraction (r)
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
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.
List four characteristics of the image formed by a concave lens of focal length 20 cm when the object is placed at a distance of 40 cm from its optical centre.
The phenomenon of change in the direction of light when it passes from one transparent medium to another is called ___________.
Explain how the formation of a rainbow occurs.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
Identify the wrong figure from the following.
Write scientific reason.
A pencil appears to be broken near the surface of water.
Explain the working of a periscope.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
Assertion and reasoning type
- Assertion: If the refractive index of the medium is high (denser medium) the velocity of the light in that medium will be small
- Reason: Refractive index of the medium is inversely proportional to the velocity of the light
The angle of incidence for a ray of light having zero reflection angle is ______.
When light passes from one medium to another the ray gets bent. This property of light is called ______.
How does the light travel?
Light bends as it passes from one medium to another. What is this phenomenon called?
Light travels fastest in a vacuum. Why?
The bending of light as it passes from one medium to another is called ______.
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
Mirage is an example of refraction and the total internal reflection of light.
A ray of light starting from diamond is incident on the interface separating diamond and water. Draw a labelled ray diagram to show. the refraction of light in this case.
