1997 General Studies, all questions

UPSC Prelims 1997 · General Studies

Question 110: Science and Technology

The working principle of a washing machine is

acentrifugation
bdialysis
creverse osmosis
ddiffusion

AnswerThe answer is (a).

A washing machine's spin cycle works by centrifugation: the drum spins fast and water is flung outwards through the holes in the drum, while the clothes stay inside. Dialysis and reverse osmosis separate substances through membranes, and diffusion is the slow spreading of particles.

Why each option is right or wrong
  • (a) Right: centrifugation throws the water out of the clothes.
  • (b) Dialysis separates small molecules through a membrane.
  • (c) Reverse osmosis forces water through a membrane under pressure.
  • (d) Diffusion is the slow spreading of particles from high to low concentration.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 1997, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.