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प्रश्न
What is refraction of light?
What is refraction of light? Explain with the help of an example.
Explain the refraction of light.
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उत्तर
- Light changes its direction when going from one transparent medium to another transparent medium. This change in direction is called the refraction of light.
- For example, the coin appears to disappear in a vessel when viewed from a specific angle. But as soon as the water is poured into the vessel at a certain level, the coin appears. This phenomenon is because light rays coming from the coin emerge out of the water and change their direction due to the refraction of light.
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संबंधित प्रश्न
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?
What are the important differences between looking at a photograph of your face and looking at yourself in a plane mirror?
A wall reflects light and a mirror also reflects light. What difference is three in the way they reflect light?
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?
The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?
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?
The image in a plane mirror is virtual and laterally inverted. What does this statement mean?
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
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 goes from water into air. Will it bend towards the normal or away from the normal?
State two effects caused by the refraction of light.
Name the phenomenon due to which a swimming pool appears less deep than it really is.
In which material do you think light rays travel faster-glass or air?
Which phenomenon of light makes the water to appear shallower than it really is?
What is meant by 'refraction of light'? Draw a labelled ray diagram to show the refraction of light.
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.
Name the phenomenon due to which a pencil partly immersed in water and held obliquely appears to be bent at the water surface.
Explain with the help of a labelled ray diagram, why a pencil partly immersed in water appears to be bent at the water surface. State whether the bending of pencil will increase or decrease if water is replaced by another liquid which is optically more dense than water. Give reason for your answer.
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of incidence?
Water is optically denser than glass.
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 |
The diagram (figure) given below shows two parallel rays 1 and 2 incident on (a) a concave mirror, (b) a convex mirror. Draw the reflected rays and mark the focus by the symbol F.
What is the cause of refraction of light when it passes from one medium to another?
Fill in the blank and Explain the completed sentences.
The change in ______ of light rays while going from one medium to another is called refraction.
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.
Choose the correct option from given alternative:
A real image is formed by the light rays after reflection or refraction when they:
(A) actually meet or intersect with each other.
(B) actually converge at a point
(C) appear to meet when they are produced in the backward direction.
(D) appear to diverge from a point.
Which of the above statements are correct?
Due to _______ pencil looks bent in water, in the given experiment.
Light changes its direction when going from one transparent medium to another transparent medium. This is called _______.
Write scientific reason.
The sun appears on the western horizon for some time after sunset.
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 four substances A, B, C, and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in
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
What is refractive index?
The deviation of light ray from its path when it travels from one transparent medium to another transparent medium is called ______.
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?
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
Twinkling of stars and Mirage are the two phenomena occurring due to refraction.
