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Question
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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Solution
We know that light refracts when it travels from one medium to another. Though the earth's atmosphere contains only air, refraction takes place because the atmosphere consists of layers of air that are at different temperatures. The layers of air that are hotter behave like an optically rarer medium and those that are cooler behave like an optically denser medium. Therefore, when light travels through these layers of air of different optical densities, bending of light, or refraction, takes place.
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RELATED QUESTIONS
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
State whether the following statement is true or false:
The planets twinkle at night due to atmospheric refraction of light.
The atmospheric refraction of light causes the twinkling of:
(a) planets only
(b) stars only
(c) planets and stars
(d) stars and satellites
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
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?
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.
Why does the sky appear blue on a clear day?
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
Explain why the planets do not twinkle but the stars twinkle.
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.
