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प्रश्न
Write scientific reason.
A pencil appears to be broken near the surface of water.
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उत्तर
- When one look at the portion of the pencil that is inside the water, light travels from water to air via glass.
- This light ray changes the medium and undergoes refraction.
- As a result, the pencil inside the water appears to be broken near the surface of water.
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संबंधित प्रश्न
If an object is placed at a distance of 10 cm in from of a plane mirror, how far would it be from its image?
Fill in the following blank with a suitable word:
When light is reflected, the angles of incidence and reflection are ............ .
Where is the image when you look at something in a mirror?
The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?
What is meant by 'reflection of light'?
Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram:
(a) Incident ray
(b) Point of incidence
(c) Normal
(d) Reflected ray
(e) Angle of incidence
(f) Angle of reflection
The image in a plane mirror is virtual and laterally inverted. What does this statement mean?
The angle of reflection is equal to the angle of incidence:
(a) always
(b) sometimes
(c) under special conditions
(d) never
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
If a ray of light goes from a rarer medium to a denser medium, will it bend towards the normal or away from it?
A ray of light travelling in glass emerges into air. State whether it will bend towards the normal or away from the normal.
A ray of light goes from water into air. Will it bend towards the normal or away from the normal?
When a ray of light passes from air into glass, is the angle of refraction greater than or less than the angle of incidence?
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
With the help of a labelled diagram, explain why a tank full of water appears less deep than it actually is.
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.
How does the light have to enter the glass:
to produce a large amount of bending?
Air is optically .......... than glass.
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
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.
What is atmospheric reflection? Explain with the help of a labelled diagram that the position of a star as seen by us is not its true position.
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 phenomenon of change in the direction of light when it passes from one transparent medium to another is called ___________.
Explain how the formation of a rainbow occurs.
The laws of reflection hold true for ______.
Due to _______ pencil looks bent in water, in the given experiment.
Why does a ray of light bend when it travels from one medium to another?
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.
What is refractive index?
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?
Which object use the reflection of light?
When light passes from one medium to another the ray gets bent. This property of light is called ______.
The ratio of the sine of the angle of incidence to the sine of ______ is constant.
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 |
The bottom of swimming pool appears to be less deep than the actual one because of
