2001 General Studies, all questions
UPSC Prelims 2001 · General Studies
Question 105: Science and Technology
When water is heated from 0 °C to 10 °C, its volume
aincreases
bdecreases
cdoes not change
dfirst decreases and then increases
AnswerThe answer is (d).
Water behaves unusually between 0 and 4 degrees C: it contracts on heating, reaching its smallest volume and greatest density at 4 degrees C. Above 4 degrees it expands like other liquids. So from 0 to 10 degrees C the volume first decreases and then increases. Remember this as the anomalous expansion of water, which lets lakes freeze from the top and keeps aquatic life alive below.
Why each option is right or wrong
- (a) Volume falls up to 4 degrees C, so it does not only increase.
- (b) Volume rises again after 4 degrees C, so it does not only decrease.
- (c) Volume changes throughout this range.
- (d) Right: first decreases up to 4 degrees C, then increases.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2001, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.