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Mains Prelims

Q32 · UPSC Prelims 2019 · Set A · Science and Technology

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For the measurement/ estimation of which of the following are satellite images/remote sensing data used?1.Chlorophyll content in the vegetation of a specific location2.Greenhouse gas emissions from rice paddies of a specific location3.Land surface temperatures of a specific locationSelect the correct answer using the code given below

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A 1 only
B 2 and 3 only
C 3 only
D 1, 2 and 3

Correct answer: (d) 1, 2 and 3

Explanation

  1. A

    1 only

    (a) 1 only. Chlorophyll/vegetation indices from satellites are real, but greenhouse-gas sensing over rice paddies and land-surface temperature are also established remote-sensing products, so 1 only is not the key.

  2. B

    2 and 3 only

    (b) 2 and 3 only. Those two are valid uses, but dropping chlorophyll is incomplete, so this is not the key.

  3. C

    3 only

    (c) 3 only. LST is only one of the three listed applications, so 3 only is not the key.

  4. D

    1, 2 and 3

    (d) 1, 2 and 3. Optical indices estimate chlorophyll/vegetation greenness; microwave and other missions constrain methane and related fluxes from rice; thermal infrared gives land-surface temperature. All three uses are live, so this is the official key.

Summary. Official key is (d) 1, 2 and 3. Remote sensing is not only pretty pictures: vegetation chlorophyll, paddy-related greenhouse gases, and surface temperature are all retrieved from satellite sensors. Honour the stored letter (d).

Same topic · past papers

UPSC has asked this before

These previous-year questions sit on the same topic. Open one to practise the earlier ask.

  1. 2026 · Q8 · General Studies · 2 marks

    Consider the following statements about the archaeological findings in Harappan towns: I. There is wide occurrence of spindle-whorls in the houses but absence of spinning wheels. II. Weights and measurement scales, complete with graduations have been discovered. III. There are houses built in large part with baked bricks, around relatively spacious courtyards, with their own wells, bathing platforms, and large rooms. Which of the following inferences can be drawn from the above statements? 1. Statement I suggests that spinning was a laborious activity done at home. 2. Statement II suggests the extent of the scientific knowledge that the Harappans possessed. 3. Statement III suggests the emergence of a common property system. Select the answer using the code given below:

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← 2019 Set A paper

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