Home PYQs UPPSC UPPSC MCQs Prelims 1994 (GS Paper I)

Question

Why does water boil at temperature below 100°C at higher altitudes?

  1. The atmospheric pressure decreases and hence boiling point is lowered
  2. The gravitational attraction is less
  3. Because of heavy winds in mountains
  4. None of the above is correct

Answer:

Option A: The atmospheric pressure decreases and hence boiling point is lowered

Detailed Solution:

The correct answer is “The atmospheric pressure decreases and hence boiling point is lowered”.

At higher altitudes, the atmospheric pressure is lower than at sea level. This decrease in pressure means that water can reach its boiling point at a lower temperature.