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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
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 is the difference between regular reflection of light and diffuse reflection of light?
What type of reflection of light takes place from a cinema screen?
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?
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
An object is placed 20 cm in front of a plane mirror. The mirror is moved 2 cm towards the object. The distance between the positions of the positions of the original and final images seen in the mirror is ______.
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?
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?
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 ______.
A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of:
(a) 0°
(b) 45°
(c) 90°
(d) 120°
A vertical ray of light strikes the horizontal surface of some water:
- What is the angle of incidence?
- What is the angle of refraction?
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.
What do you understand by refraction of light?
What is the cause of refraction of light when it passes from one medium to another?
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.
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 .
List in proper sequence the steps of the experiment for determining the approximate focal length of a given concave mirror by obtaining the image of a distant object.
A real image is formed by the light rays after reflection or refraction when they:
- actually meet or intersect with each other.
- actually converge at a point.
- appear to meet when they are produced in the backward direction.
- appear to diverge from a point.
Which of the above statements are correct?
Due to _______ pencil looks bent in water, in the given experiment.
Right or wrong sentence.
The incident rays and refracted rays are on opposite sides of the column.
Write scientific reason.
The bottom of a pond appears raised.
Write a 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.
Observe the given figure and name the following.
| Ray AB | |
| Ray NM | |
| Ray MD | |
| ∠ r |
Observe the given figure and write appropriate phenomenon of light in the box.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
The refractive index of a transparent medium is always greater than ______.
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
Which surface will not reflect most of the light falling on them?
Light travels fastest in a vacuum. Why?
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
When a ray of light travels normal to the given surface, then the angle of refraction is ______.
