Advertisements
Advertisements
प्रश्न
A pencil when dipped in water in a glass tumbler appears to be bent at the interface of air and water. Will the pencil appear to be bent to the same extent, if instead of water we use liquids like, kerosene or turpentine. Support your answer with reason.
Advertisements
उत्तर
The pencil when dipped in water in a glass tumbler appears to be bent at the interface of air and water due to the refraction of light. The refractive index of different mediums is different. The refractive index of kerosene and turpentine is more than the water, due to this the pencil will appear to bend more in case of kerosene or turpentine than that in case of water.
Therefore the pencil will not appear to be bent to the same extent, if instead of water we use liquids like, kerosene or turpentine.
APPEARS IN
संबंधित प्रश्न
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?
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 a plane mirror. The correct time is:
Figure
(a) 2.25
(b) 2.35
(c) 6.45
(d) 9.25
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?
As light rays pass from water into glass, are they refracted towards the normal or away from the normal?
When a light ray passes from air into glass, what happens to its speed? Draw a diagram to show which way the ray of light bends.
Light travelling from a denser medium to a rarer medium along a normal to the boundary:
(a) is refracted towards the normal
(b) is refracted away from the normal
(c) goes along the boundary
(d) is not refracted
How does the light have to enter the glass:
for no refraction to happen?
The speed of light is more in glass than in water.
When a ray of light travels from water to air, it bends ............. the normal.
A ray of light A incident from air suffers partial reflection and refraction at the boundary of water.

- Complete the diagram showing (i) the reflected ray B and (ii) the refracted ray C.
- How are the angles of incidence i and refraction r related?
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 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 .
Observe the given figure and name the following.

| Ray AB | |
| Ray NM | |
| Ray MD | |
| ∠ r |
Explain the working of a periscope.
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.
When light passes from one medium to another the ray gets bent. This property of light is called ______.
Light is refracted or bent while going from one medium to another because of its ______ changes.
A water tank appears shallower when it is viewed from the top due to refraction.
Under what circumstances there won’t be any refraction of light when it enters from one medium to another?
