UPSC Prelims 2020— Question 68

This question tests solar water pumps. The key concept is: Solar photovoltaic systems can power both surface and submersible pumps and can drive both centrifugal and positive-displacement/piston-type pumps when appropriately designed. Therefore neither statement is universally correct. The verified answer for the uploaded Set-B paper is option D. Option A — 1 only: This is not the correct option. The option does not match the verified combination or conclusion. The decisive point is the distinction explained above: Solar photovoltaic systems can power both surface and submersible pumps and can drive both centrifugal and positive-displacement/piston-type pumps when appropriately designed. Therefore neither statement is universally correct. Therefore this alternative should be eliminated even if part of its wording appears plausible in isolation. Option B — 2 only: This is not the correct option. The option does not match the verified combination or conclusion. The decisive point is the distinction explained above: Solar photovoltaic systems can power both surface and submersible pumps and can drive both centrifugal and positive-displacement/piston-type pumps when appropriately designed. Therefore neither statement is universally correct. Therefore this alternative should be eliminated even if part of its wording appears plausible in isolation. Option C — Both 1 and 2: This is not the correct option. The option does not match the verified combination or conclusion. The decisive point is the distinction explained above: Solar photovoltaic systems can power both surface and submersible pumps and can drive both centrifugal and positive-displacement/piston-type pumps when appropriately designed. Therefore neither statement is universally correct. Therefore this alternative should be eliminated even if part of its wording appears plausible in isolation. Option D — Neither 1 and 2: This is the correct option. It matches the verified conclusion because Solar photovoltaic systems can power both surface and submersible pumps and can drive both centrifugal and positive-displacement/piston-type pumps when appropriately designed. Therefore neither statement is universally correct. The wording of the option is consistent with the governing concept tested by the question. For UPSC-style elimination, first identify the exact proposition being tested, then evaluate each statement independently before comparing the answer codes. Avoid treating a broad or absolute statement as correct merely because its general theme is familiar. The precise qualifiers in the question—such as 'all', 'only', 'cannot', 'largest', 'always' or a specific institutional role—often determine the answer. On that basis, option D is the verified answer.