Please select a subject first
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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
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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?
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By how much time the day would have been shorter if the earth had no atmosphere?
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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?
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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?
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State one effect produced by the scattering of light by the atmosphere.
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Why does the sky appear blue on a clear day?
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What causes the scattering of blue component of sunlight in the atmosphere?
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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
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A star sometimes appears brighter and some other times fainter. What is this effect called? State the reason for this effect.
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The stars appear higher from horizon than they actually are. Explain why it is so.
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Explain why the planets do not twinkle but the stars twinkle.
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The air layer of the atmosphere whose temperature is less than the hot layer behave as optically:
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Refraction of light by the earth’s atmosphere due to variation in air density is called ____________.
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Assertion: Sky appears blue in the day time.
Reason: White light is composed of seven colours.
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Explain the refraction of light through a triangular glass prism using a labelled ray diagram. Hence define the angle of deviation.
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How does refraction take place in the atmosphere? Why do stars twinkle but not the planets?
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What happens at the synapse between two neurons?
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The gap between two neurons is called a ______.
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What is the function of receptors in our body?
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