Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
In an open room, the temperature is 20^ C and the dew point is 10^ C . If the temperature of the room falls to 15^ C , determine the new dew point.
Options
- A15^ C
- B10^ C
- C12.5^ C
- D5^ C
Correct answer
B. 10^ C
Step-by-step solution
The dew point is the temperature at which the water vapor present in the air becomes saturated. It depends only on the partial pressure of water vapor in the air. In an open room, the total pressure and the mole fraction of water vapor remain constant. As the temperature falls from 20^ C to 15^ C , no condensation occurs because the new temperature is still above the initial dew point of 10^ C . Since no moisture is added or removed and the partial pressure of water vapor remains constant, the temperature required