UPSC Prelims 2020 GS Paper I · Q88 of 99 Economy medium

With reference to solar water pumps, consider the following statements : 1. Solar power can be used for running surface pumps and not for submersible pumps. 2. Solar power can be used for running centrifugal pumps and not the ones with piston. Which of the statements given above is/are correct ?

  1. (a) 1 only
  2. (b) 2 only
  3. (c) Both 1 and 2
  4. (d) Neither 1 nor 2 ✓ UPSC's answer

Why the answer is (d)

• Solar water pumps run on DC or AC motors powered by photovoltaic panels; the motor type, not the energy source, decides the pump design.

• Statement 1 is wrong: solar power drives both surface pumps and submersible pumps — PM-KUSUM in fact installs mostly submersible solar pumps.

• Statement 2 is wrong: solar power can run centrifugal pumps as well as positive-displacement (piston/helical-rotor) pumps, which are common for deep low-yield wells.

• Hence neither 1 nor 2, option (d).

Why the other options are wrong

(a) 1 only
Statement 1 is wrong: submersible solar pumps are common.
(b) 2 only
Statement 2 is wrong: piston pumps can be solar-powered.
(c) Both 1 and 2
Both statements are wrong.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2020, held on 4 October 2020. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

Practise this paper free