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Question
Why do stars seem higher than they actually are? Illustrate your answer with the help of a diagram.
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Solution
Stars seem higher than they actually are because of the phenomenon of atmospheric refraction. This can be understood with the help of given diagram. When the light from a star descends to the earth's surface, it passes through the different layers of the atmosphere. The atmospheric air at higher levels is rarer and the air near the earth's surface is denser, and the light from the star bends more sharply when it passes through the denser layer of air.
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RELATED QUESTIONS
Explain why the planets do not twinkle.
The correct sequencing of angle of incidence, angle of emergence, angle of refraction and lateral displacement shown in the following diagram by digits 1, 2, 3 and 4 is:
(a) 2, 4, 1, 3
(b) 2, 1, 4, 3
(c) 1, 2, 4, 3
(d) 2, 1, 3, 4
Name the phenomenon which causes the twinkling of stars.
Name two effects produced by the atmospheric refraction.
Atmospheric refraction causes advance sunrise and delayed sunset. By how much time is:
sunset delayed?
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(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
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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.
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- Do you think that the students’ conclusion is correct?
Why does the sky appear blue on a clear day?
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(a) twinkling of stars at night
(b) sun appearing higher in the sky than it actually is
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