If 1 litre of water weighs 1 kg, then how many cubic millimetres of water will weigh 0·1 gm?
- (a) 1
- (b) 10
- (c) 100 ✓ UPSC's answer
- (d) 1000
Why the answer is (c)
• 1 litre of water weighs 1 kg, which is equivalent to 1000 grams.
• 1 litre is equal to 1000 cubic centimetres (cm³).
• Therefore, 1000 cm³ of water weighs 1000 grams, meaning 1 cm³ of water weighs 1 gram.
• The question asks for the volume of water that weighs 0.1 grams.
• Since 1 cm³ weighs 1 gram, 0.1 cm³ weighs 0.1 grams.
• Convert 0.1 cm³ to cubic millimetres (mm³): 1 cm³ = 1000 mm³, so 0.1 cm³ = 0.1 × 1000 = 100 mm³.
Why the other options are wrong
- (a) 1
- 1 mm³ of water weighs 0.001 grams, not 0.1 grams.
- (b) 10
- 10 mm³ of water weighs 0.01 grams, not 0.1 grams.
- (d) 1000
- 1000 mm³ of water weighs 1 gram, not 0.1 grams.
Asked in the CSAT Paper II 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.