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प्रश्न
Observe the given figure and name the following.
| Ray AB | |
| Ray NM | |
| Ray MD | |
| ∠ r |
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उत्तर
| Ray AB | Incident ray |
| Ray NM | Refracted ray |
| Ray MD | Emergent ray |
| ∠ r | Angle of refraction |
संबंधित प्रश्न
What is refraction of light?
State whether the following statement is true of false:
A student says that we can see an object because light from our eyes is reflected back by the object.
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?
What are the important differences between looking at a photograph of your face and looking at yourself in a plane mirror?
A wall reflects light and a mirror also reflects light. What difference is three in the way they reflect light?
An extended object in the form of an arrow pointing upward has been placed in front of a plane mirror. Draw a labelled ray-diagram to show the formation of its image.
The image of an object formed by a plane mirror is:
(a) virtual
(b) real
(c) diminished
(d) upside-down
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:
Explain how to read the following message which was found on some blotting paper:
If a ray of light goes from a rarer medium to a denser medium, will it bend towards the normal or away from it?
State two effects caused by the refraction of light.
When a ray of light passes from air into glass, is the angle of refraction greater than or less than the angle of incidence?
Which phenomenon of light makes the water to appear shallower than it really is?
What is meant by ‘refraction of light’?
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?
Explain with the help of a labelled ray diagram, why a pencil partly immersed in water appears to be bent at the water surface. State whether the bending of pencil will increase or decrease if water is replaced by another liquid which is optically more dense than water. Give reason for your answer.
How does the light have to enter the glass:
to produce a large amount of bending?
Air is optically .......... than glass.
When a ray of light travels from water to air, it bends ............. the normal.
What do you understand by refraction of light?
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 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 .
The laws of reflection hold true for ______.
The incident rays and refracting rays are on opposite sides of the normal.
Write scientific reason.
The coin disappears in a vessel as it is seen from a specific location. But as soon as the water is poured into the vessel to a certain level, the coin appears.
Numerical problems.
The speed of light in water is 2.25 × 108 ms–1. If the speed of light in vacuum is 3 × 108 ms–1, calculate the refractive index of water.
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 angle of incidence from air to glass at the point O on the hemispherical glass slab is.
Noor, a young student, was trying to demonstrate some properties of light in her Science project work. She kept ‘X’ inside the box (as shown in the figure) and with the help of a laser pointer made light rays pass through the holes on one side of the box. She had a small butter-paper screen to see the spots of light being cast as they emerged.
Her friend noted the following observations from this demonstration:
- Glass is optically rarer than air.
- Air and glass allow light to pass through them with the same velocity.
- Air is optically rarer than glass.
- Speed of light through a denser medium is faster than that of a rarer medium.
- The ratio: sin of angle of incidence in the first medium to the ratio of sin of angle of refraction in the second medium, gives the refractive index of the second material with respect to the first one.
Which one of the combinations of the above statements given below is correct.
Mirage is an example of refraction and the total internal reflection of light.
Twinkling of stars and Mirage are the two phenomena occurring due to refraction.
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
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 |
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.
