Dew Point and Humidity

Q.

A cup of tea cools from ${80}^{\circ }C$ to ${60}^{\circ }C$ in one minute.

The ambient temperature is ${30}^{\circ }C$.

In coolingfrom ${60}^{\circ }C$ to ${50}^{\circ }Citwilltakenearly$

1. 30 seconds

2. 60 seconds

3. 90 seconds

4. 50 seconds

Q. A glass contains some water at room temperature ${20}^{\circ }C$. Refrigerated water is added to it slowly. When the temperature of the glass reaches ${10}^{\circ }C$, small droplets condense on the outer surface. Calculate the relative humidity in the room. The boiling point of water at a pressure of 17.5 mm of mercury is ${20}^{\circ }C$ and at 8.9 mm of mercury it is ${10}^{\circ }C$.

1. $60\%$
2. $75\%$
3. $51\%$
4. $35\%$

Q. The temperature and the dew point in an open room are $20{}^{\circ }C$ and $10{}^{\circ }C$. If the room temperature drops to $15{}^{\circ }C$, what will be the new dew point?

1. $10{}^{\circ }C$
2. $11{}^{\circ }C$
3. $15{}^{\circ }C$
4. $20{}^{\circ }C$

Q. The weather report reads,
“Temperature: $20{}^{\circ }C$,
Relative humidity: $100\%$”.
What is the dew point?

1. Less than $20{}^{\circ }C$
2. $20{}^{\circ }C$
3. More than $20{}^{\circ }C$
4. Can’t be said.