2015 GS Paper I, all questions

UPSC Prelims 2015 · GS Paper I

Question 71: Science and Technology

In which of the following activities are Indian Remote Sensing (IRS) satellites used?

  1. 1.Assessment of crop productivity
  2. 2.Locating groundwater resources
  3. 3.Mineral exploration
  4. 4.Telecommunications
  5. 5.Traffic studies

Select the correct answer using the code given below.

a1, 2 and 3 only
b4 and 5 only
c1 and 2 only
d1, 2, 3, 4 and 5

AnswerUPSC’s answer is (a).

Indian Remote Sensing satellites observe the Earth's surface, so they are used for assessing crop productivity, locating groundwater resources and exploring minerals, besides forestry, land use and disaster monitoring. Telecommunication is done by communication satellites, such as the INSAT and GSAT series, and traffic studies are not an IRS application. So only 1, 2 and 3 are correct.

  • 1. IRS imagery is used to estimate crop area and productivity.
  • 2. IRS data helps locate groundwater potential zones.
  • 3. IRS data supports mineral exploration.
  • 4. Telecommunication is done by communication satellites such as INSAT and GSAT.
  • 5. Traffic studies are not an IRS application.

How you could have got this

  1. If you were sure statement 3 is correct, (b) and (c) go: each of them leaves 3 out.

    What you needed to know: IRS data supports mineral exploration.

  2. Then, if you were sure statement 4 is not correct, (d) goes: it includes 4.

    What you needed to know: Telecommunication is done by communication satellites such as INSAT and GSAT.

Only (a) is left. You didn’t need statements 1, 2 or 5.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong
  • (a) Correct: crop assessment, groundwater and mineral exploration use IRS data.
  • (b) Wrong: telecommunication and traffic studies are not IRS tasks.
  • (c) Incomplete: mineral exploration also uses IRS data.
  • (d) Wrong: telecommunication is done by INSAT and GSAT satellites, and traffic studies are not an IRS use.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2015, General Studies Paper I, Series A. The paper on upsc.gov.in.