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प्रश्न
How does refraction take place in the atmosphere? Why do stars twinkle but not the planets?
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.
The atmospheric refraction of light causes the twinkling of:
(a) planets only
(b) stars only
(c) planets and stars
(d) stars and satellites
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
We know that light refracts (or bends) when it goes from one medium to another. Now, the atmosphere contains only air. Then how does light get refracted on passing through only air in the atmosphere?
By how much time the day would have been shorter if the earth had no 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.
What does the student mean by saying that the sun can be seen after it has set?
What causes the scattering of blue component of sunlight in the atmosphere?
Which of the following is not caused by the atmospheric refraction of light?
(a) twinkling of stars at night
(b) sun appearing higher in the sky than it actually is
(c) sun becoming visible two minutes before actual sunrise
(d) sun appearing red at sunset
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.
