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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.
Name the phenomenon which causes the twinkling of stars.
State whether the following statement is true or false:
The planets twinkle at night due to atmospheric refraction of light.
Why do stars seem higher than they actually are? Illustrate your answer with the help of a diagram.
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
As light from a far off star comes down towards the earth:
(a) it bends away from the normal
(b) it bends towards the normal
(c) it does not bend at all
(d) it is reflected back
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
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?
- Do you think that the students’ conclusion is correct?
State one effect produced by the scattering of light by the atmosphere.
Why does the sky appear blue on a clear day?
The air layer of the atmosphere whose temperature is less than the hot layer behave as optically:
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.
