The Earth's atmosphere is mainly heated by which one of the following ?
- A.Short wave solar radiation
- B.Reflected solar radiation
- C.Long wave terrestrial radiation
- D.Scattered solar radiation
Correct answer
Explanation
The correct answer is C, Long wave terrestrial radiation. The atmosphere is heated mainly from below, by the long-wave heat the Earth's surface gives off, not directly by sunlight.
Incoming solar radiation, or insolation, is mostly short-wave, and the atmosphere lets most of it pass through. The land and oceans absorb it, warm up and then radiate energy back as long-wave infrared, or terrestrial radiation. Carbon dioxide, water vapour and other greenhouse gases absorb this long-wave radiation readily and warm the air. That is why temperature in the troposphere usually falls with height, by about 6.5 °C per kilometre, the normal lapse rate: the air nearest the heated ground is the warmest.
A is wrong because short-wave solar radiation mostly passes through the air and heats the surface, not the atmosphere.
B is wrong because reflected radiation, the Earth's albedo of about 30%, goes back to space without heating the air.
D is wrong because scattering by air molecules makes the sky blue but adds little heat.
Exam tip: Sun gives short waves, Earth gives long waves; the atmosphere is heated from below.
Practice Questions
View allWhich one of the following is a cold ocean current ?
- A.Brazilian Current
- B.Gulf Stream
- C.North Equatorial Current
- D.California Current
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It flows south along the west coast of North America, carrying cold water from higher latitudes towards the equator. As a rule, currents moving from the poles towards the equator are cold, and those moving from the equator towards the poles are warm.
Read the full explanation →Rani told her friends that last year she did boating in four different lakes, namely, Loktak, Barapani, Kolleru and Pulicat. Which of the following States did she visit?
- A.Manipur, Meghalaya, Kerala, Tamil Nadu
- B.Manipur, Meghalaya, Andhra Pradesh, Tamil Nadu
- C.Mizoram, Assam, Kerala, Tamil Nadu
- D.Mizoram, Assam, Andhra Pradesh, Tamil Nadu
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Loktak is in Manipur, Barapani in Meghalaya, Kolleru in Andhra Pradesh, and Pulicat on the Andhra Pradesh–Tamil Nadu border. Loktak is the largest freshwater lake in north-east India, famous for its floating islands of vegetation called phumdis; Keibul Lamjao, the only floating national park in the world, lies on it.
Read the full explanation →Consider the following statements on 'Fog' : 1. Fog is simply a cloud that forms close to the ground. 2. Radiation fog is associated with radiation cooling of the land at night. 3. Advection fog forms when moisture is blown over a cold surface and is chilled by contact. Which of the statements given above are correct ?
- A.1 and 2 only
- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
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All three statements are correct descriptions of fog and its two main types. Fog forms when air near the ground cools to its dew point and its water vapour condenses on tiny dust and smoke particles, so it is in effect a cloud at or near ground level.
Read the full explanation →Salal Power Project is situated on which one among the following rivers?
- A.Chenab
- B.Jhelum
- C.Nubra
- D.Shyok
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The Salal hydroelectric project is a run-of-the-river project on the Chenab in the Reasi district of Jammu and Kashmir. Built and run by NHPC, Salal has an installed capacity of 690 MW and was the first project India built under the Indus Waters Treaty of 1960 on a western river.
Read the full explanation →India's territorial limit extends towards the sea up to
- A.10 nautical miles
- B.12 nautical miles
- C.14 nautical miles
- D.15 nautical miles
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India's territorial waters, where it has full sovereignty, extend 12 nautical miles (about 22.2 km) from the baseline of its coast.
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