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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.
APPEARS IN
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 |
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?
A ray of light strikes a plane mirror such that its angle of incidence is 30°. What angle does the reflected ray make with the mirror surface?
What is lateral inversion? Explain by giving a suitable example.
Write the word AMBULANCE as it would appear when reflected in a plane mirror. Why is it sometimes written in this way (as its mirror image) on the front of an ambulance?
Which type of reflection of light leads to the formation of images?
What type of reflection of light takes place from a cinema screen?
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?
Write all the capital letters of the alphabet which look the same in a plane mirror.
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.
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 ______.
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 ______.
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?
A ray of light travelling in air is incident on a rectangular glass block and emerges out into the air from the opposite face. Draw a labelled ray diagram to show the completer path of this ray of light. Mark the two points where the refraction of light takes place. What can you say about the final direction of ray of light?
Light travels more quickly through water than through glass.
Which is optically denser : water or glass?
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.
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of incidence?
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of refraction?
Light travels at a lower speed in water than in air.
When a ray of light travels from air to glass, it bends .......... the normal.
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to air |
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?
We can see the sun even when it is little below the horizon because of ______.
Choose and write the correct option.
If we gradually increase the angle of incidence of a ray of light passing through prism then …..
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.
Explain the working of a periscope.
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
If a beam of red light and a beam of violet light are incident at the same angle on the inclined surface of a prism from air medium and produce angles of refraction r and v respectively, which of the following is correct?
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.
Light travels fastest in a vacuum. Why?
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 |
In refraction of light through a glass slab, the directions of the incident ray and the refracted ray are ______.
