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प्रश्न
Write scientific reason.
The bottom of a pond appears raised.
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उत्तर
- The rays of light coming from the bottom of a pond bend away from the normal as they travel from water (denser medium) to air (rarer medium).
- Hence, they appear to come from a point above the actual point from which they come. Therefore, the bottom of the pond appears raised.
संबंधित प्रश्न
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.
What are the important differences between looking at a photograph of your face and looking at yourself in a plane mirror?
What is the difference between regular reflection of light and diffuse reflection of light?
The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?
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.
State the uses of plane mirrors.
Explain why, though both a plane mirror and a sheet of paper reflect light but we can see the image of our face in a plane mirror but not in a sheet of paper.
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?
Explain how to read the following message which was found on some blotting paper:
If a ray of light goes form a denser medium to a rarer medium, will it bend towards the normal or away from the normal?
A ray of light travelling in glass emerges into air. State whether it will bend towards the normal or away from the normal.
Name the phenomenon due to which a swimming pool appears less deep than it really is.
When a ray of light passes from air into glass, is the angle of refraction greater than or less than the angle of incidence?
As light rays pass from water into glass, are they refracted towards the normal or away from the normal?
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
Fill in the following blank with suitable word:
Light bends when is passes from water into air. We say that it is ............
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.
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.
- 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.
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.
When a ray of light travels from air to glass, it bends .......... the normal.
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
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.
Explain how the formation of a rainbow occurs.
The speed of light varies in different media.
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.
Explain with diagrams how refraction of incident light takes place from
- rarer to denser medium
- denser to rarer medium
- normal to the surface separating the two media.
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 deviation of light ray from its path when it travels from one transparent medium to another transparent medium is called ______.
How does the light travel?
The bending of light as it passes from one medium to another is called ______.
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
Under what circumstances there won’t be any refraction of light when it enters from one medium to another?
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.
