Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
A 50 m ^3 volume of saturated vapour is cooled from 30^ C to 20^ C . Calculate the mass of the condensed water. At 30^ C , the absolute humidity of saturated water vapour is 30 g m ⁻³ , while at 20^ C it is 16 g m ⁻³ .
Options
- A800 g
- B1500 g
- C700 g
- D350 g
Correct answer
C. 700 g
Step-by-step solution
The initial mass of water vapour present in the volume at 30^ C is given by the product of volume and absolute humidity. m₁ = 50 m ³ 30 g m ⁻³ = 1500 g When the vapour is cooled to 20^ C , the maximum mass of water vapour that can be held in the same volume is: m₂ = 50 m ³ 16 g m ⁻³ = 800 g The excess water vapour will condense into liquid water. The mass of the condensed water is: m = m₁ - m₂ = 1500 g - 800 g = 700 g