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प्रश्न
Write scientific reason.
The sun appears on the western horizon for some time after sunset.
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उत्तर
- As ray of light from the Sun enters the earth’s atmosphere, it follows a curved path due to refraction, before reaching the observer.
- This makes the apparent position of the Sun slightly higher than the actual position for the observer.
- Hence, due to the atmospheric refraction of sunlight, the observer on the earth continues to see the setting Sun for two minutes after the Sun has dipped below the horizon, thus delaying the sunset.
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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 |
Which property of light makes a pencil cast a shadow when it is held in front of a light source?
The letter F is placed in front of a plane mirror:
How would its image look like when seen in a plane mirror?
Which type of reflection of light leads to the formation of images?
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.
State and explain the laws of reflection of light at a plane surface (like a plane mirror), With the help of a labelled ray-diagram. Mark the angles of 'incidence' and 'reflection' clearly on the diagram. If the angle of reflection is 47.5°, what will be the angle of incidence?
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:
A ray of light travelling in glass emerges into air. State whether it will bend towards the normal or away from the normal.
In which material do you think light rays travel faster-glass or air?
State whether the following statement is true or false:
Refraction occurs because light slows down in denser materials.
Why does a ray of light bend when it travels from one medium to another?
What is meant by 'refraction of light'? Draw a labelled ray diagram to show the refraction of light.
Light travels more quickly through water than through glass.
Which is optically denser : water or glass?
Light travels more quickly through water than through glass.
If a ray of light passes from glass into water, which way will it bend : 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.
With the help of a labelled diagram, explain why a tank full of water appears less deep than it actually is.
Show the lateral displacement of the ray on the diagram.
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of refraction?
The depth of a pond when seen from above appears to be less.
Air is optically .......... than glass.
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.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
In the above diagram light is travelling through different media. It is noted by a scientist that ∠1= ∠3 = ∠4 but ∠2 < ∠1. Which of the following statement would be correct?
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.
The phenomenon of light passing through the object is called ______.
The bending of light as it passes from one medium to another is called ______.
The ratio of the sine of the angle of incidence to the sine of ______ is constant.
Mirage is an example of refraction and the total internal reflection of light.
A water tank appears shallower when it is viewed from the top due to refraction.
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.
How do twinkling stars occur? (or) what is the cause of the twinkling of stars?
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.
