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प्रश्न
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.
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उत्तर
Refraction of light by earth’s atmosphere is called at,ospheric refraction
Since the atmosphere bends the starlight towards the normal, the apparent position of the star is slightly different from actual position.
The star appears slightly higher from actual position when viewed near horizon.
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संबंधित प्रश्न
Where is the image when you look at something in a mirror?
Explain how to read the following message which was found on some blotting paper:
A ray of light passes from air into a block of glass. Does it bend towards the normal or away from it?
Show the lateral displacement of the ray on the diagram.
When a ray of light travelling in glass enters into water obliquely:
(a) it is refracted towards the normal
(b) it is not refracted at all
(c) it goes along the normal
(d) it is refracted away from the normal
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
Explain with diagrams how refraction of incident light takes place from
- rarer to denser medium
- denser to rarer medium
- normal to the surface separating the two 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.
Light travels fastest in a vacuum. Why?
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
