2008 General Studies, all questions
UPSC Prelims 2008 · General Studies
Question 126: Basic Numeracy
How can the height of a person who is six feet tall be expressed (approximately) in nanometres?
a183 × 10⁶ nanometres
b234 × 10⁶ nanometres
c183 × 10⁷ nanometres
d234 × 10⁷ nanometres
AnswerThe answer is (c).
Six feet is 6 x 0.3048 m = 1.8288 m, about 1.83 m. One metre is 10^9 nanometres, so 1.83 m = 1.83 x 10^9 nm = 183 x 10^7 nm. Convert the unit first (feet to metres) and then scale by powers of ten.
Why each option is right or wrong
- (a) 183 x 10^6 nm is 0.183 m, ten times too small.
- (b) 234 x 10^6 nm is 0.234 m, far too small.
- (c) 183 x 10^7 nm is 1.83 m, about six feet.
- (d) 234 x 10^7 nm is 2.34 m, too tall.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2008, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.