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प्रश्न
How does refraction take place in the atmosphere? Why do stars twinkle but not the planets?
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उत्तर
There are several layers present in the atmosphere. The upper layer is optically rare, but the bottom layer is optically denser. When light passes through thicker and denser layers of the atmosphere, it bends towards the normal. As the stars are present very far away from us, the light coming from them get refracted multiple times and that results in the twinkling of the stars.
The planets are present much closer to the earth as compared to stars which make planets look like an extended source of light, not like a point-sized source of light as stars appear. This makes planets look stationary, not twinkling like stars.
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संबंधित प्रश्न
What is atmospheric refraction? Use this phenomenon to explain the following natural events:
Twinkling of stars
Draw diagrams to illustrate your answers.
What is atmospheric refraction? Use this phenomenon to explain the following natural events:
Advanced sun-rise and delayed sun-set.
Draw diagrams to illustrate your answers.
Explain why the planets do not twinkle.
Name the phenomenon which causes the twinkling of stars.
Name two effects produced by the atmospheric refraction.
State whether the following statement is true or false:
The planets twinkle at night due to atmospheric refraction of light.
What is atmospheric refraction?
The atmospheric refraction of light causes the twinkling of:
(a) planets only
(b) stars only
(c) planets and stars
(d) stars and satellites
The stars twinkle but the planets do not twinkle at night because:
(a) the stars are small but the planets are large
(b) the stars are very large but planets are small
(c) the stars are much nearer but planets are far off
(d) the stars are far off but planets are nearer to earth
Due to atmospheric refraction of sunlight, the time from sunrise to sunset is lengthened by about:
(a) 6 minutes
(b) 2 minutes
(c) 4 minutes
(d) 5 minutes
The day is longer on the earth by about 4 minutes because:
(a) the earth is round in shape
(b) the earth rotates on its axis
(c) the earth revolves around the sun
(d) the earth has atmosphere
A student claims that because of atmospheric refraction, the sun can be seen after it has set, and the day is, therefore, longer than if the earth had no atmosphere.
Do you think that the students conclusion is correct?
State one effect produced by the scattering of light by the atmosphere.
A star sometimes appears brighter and some other times fainter. What is this effect called? State the reason for this effect.
Explain why the planets do not twinkle but the stars twinkle.
Refraction of light by the earth’s atmosphere due to variation in air density is called ____________.
Assertion: Sky appears blue in the day time.
Reason: White light is composed of seven colours.
Explain the refraction of light through a triangular glass prism using a labelled ray diagram. Hence define the angle of deviation.
