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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.
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 |
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.
The letter F is placed in front of a plane mirror:
- How would its image look like when seen in a plane mirror?
- What is the name of the phenomenon involved?
Which type of reflection of light leads to the formation of images?
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?
Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram:
- Incident ray
- Point of incidence
- Normal
- Reflected ray
- Angle of incidence
- Angle of reflection
Explain why, though both a plane mirror and a sheet of paper reflect light but we can see the image of our face in a plane mirror but not in a sheet of paper.
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
A man stands 10 m in front of a large plane mirror. How far must the walk before he is 5 m away from his image?
A man sits in an optician's chair looking into plane mirror which is 2 m away from him and views the image of a chart which faces the mirror and is 50 cm behind his head. How far away from his eyes does the chart appear to be?
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 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.
As light rays pass from water into glass, are they refracted towards the normal or away from the normal?
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
Light travels more quickly through water than through glass.
- Which is optically denser: water or glass?
- If a ray of light passes from glass into water, which way will it bend: towards the normal or away from the normal?
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 ray of light when passes from glass to air, bends towards the normal.
The speed of light is more in glass than in water.
The depth of a pond when seen from above appears to be less.
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.
Define the principal focus of a concave mirror.
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.
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?
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
The speed of light varies in different media.
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.
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
You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most?
The angle of incidence from air to glass at the point O on the hemispherical glass slab is.
Which object use the reflection of light?
How does the light travel?
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
In refraction of light through a glass slab, the directions of the incident ray and the refracted ray are ______.
When a ray of light travels normal to the given surface, then the angle of refraction is ______.
According to the first law of refraction, the incident ray, the refracted ray, and the normal at the point of incidence:
