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प्रश्न
Explain why the planets do not twinkle.
Explain why, the planets do not twinkle at night.
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उत्तर
Planets are much closer to the Earth and are seen as extended sources. So, a planet may be considered a collection of a large number of point-sized light sources. Although light coming from individual point-sized sources flickers but the total amount of light entering our eye from all the individual point-sized sources averages out to be constant. Thereby, planets appear equally bright and there is no twinkling of planets.
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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 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.
Atmospheric refraction causes advance sunrise and delayed sunset. By how much time is:
sunset delayed?
Fill in the following blank with suitable word:
We can see the sun about ................ minutes before the actual sunrise and about ................ minutes after the actual sunset because of atmospheric ................
Why do stars seem higher than they actually are? Illustrate your answer with the help of a diagram.
What is atmospheric refraction?
The twinkling of stars is due to atmospheric:
(a) reflection of light
(b) dispersion of light
(c) interference of light
(d) refraction of light
The stars appear higher in the sky than they actually are, due to:
(a) diffraction of light
(b) scattering of light
(c) refraction of light
(d) reflection of light
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
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?
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.
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
The stars appear higher from horizon than they actually are. Explain why it is so.
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.
