2010 General Studies, all questions

UPSC Prelims 2010 · General Studies

Question 74: Geography

Which one of the following reflects back more sunlight as compared to other three ?

aSand desert
bPaddy crop land
cLand covered with fresh snow
dPrairie land

AnswerThe answer is (c).

Albedo is the share of incoming sunlight that a surface reflects. Fresh snow has the highest albedo of the options, reflecting roughly 80 to 90 per cent of sunlight, whereas sand desert reflects perhaps a quarter to two-fifths, and crops and grassland reflect only about 15 to 25 per cent because vegetation absorbs light for photosynthesis. Remember: snow and ice have high albedo, which is why melting ice speeds warming.

Why each option is right or wrong
  • (a) Sand reflects well but far less than fresh snow.
  • (b) A paddy field absorbs most sunlight.
  • (c) Right: fresh snow has the highest reflectivity.
  • (d) Prairie grass absorbs most sunlight.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2010, General Studies, Series A. The paper on upsc.gov.in.