Relative Humidity

Q. The ratio of actual mass of vapour content in air to the mass of vapour required to make the air saturated is called .

1. absolute humidity
2. relative humidity
3. humidity
4. dew point

Q. At dew point. Relative Humidity is

1. 10%
2. 20%
3. 50%
4. 100%

Q.

What is dry oxygen?

Q. The units of relative humidity are:

1. kg-m${}^{-3}$
2. kg
3. kg-m${}^2$
4. none of these

Q. The relative humidity on a day when partial pressure of water vapour is $0.012\times {10}^{5}Pa$ at ${12}^{o}C$ is (Take vapour pressure of water at this temperature as $0.016\times {10}^5$ Pa)

1. 70%
2. 40%
3. 75%
4. 25%

Q. The relative humidity on a day when partial pressure of water vapour is $0.012\times {10}^{5}Pa$ at ${12}^{\circ }C$ is
(Take vapour pressure of water at this temperature as $0.016\times {10}^{5}Pa)$.

1. $25$%
2. $75$%
3. $40$%
4. $70$%

Q. On a day during the Monsoon season, the relative humidity at a place is 90% and the temperature is ${15}^{\circ }$ (C) The saturation vapour pressure of water at this temperature is $0.0169\times {10}^5$ Pa. The partial pressure of water vapour in the air on that day is

1. $0.9\times {10}^5$ Pa
2. $0.0169\times {10}^5$ Pa
3. $0.0152\times {10}^5$ Pa
4. $1.0\times {10}^5$ Pa

Q. Relative humidity depends on temperature and pressure.

1. False
2. True

Q. We feel most comfortable at relative humidity at:

1. < 50%
2. > 50%
3. 50%
4. 100%

Q. If RH is high:

1. we feel sultry
2. we perspire less
3. clothes do not dry easily
4. all the above are correct

Q. Relative humidity is the percentage of the

1. absolute humidity value to the amount of humidity actually present.
2. increase of humidity/ absolute humidity.
3. amount of humidity actually present to the absolute humidity
4. none of these

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

Q. At dew point. RH is _______.

1. 10%
2. 30%
3. 50%
4. 100%

Q. The most comfortable value for Relative Humidity is

1. 10%
2. 20%
3. 50%
4. 90%

Q. The most comfortable value for RH is ______.

1. 10%
2. 30%
3. 50%
4. 90%

Q. At dew point. RH of the air is:

1. $10\%$
2. $20\%$
3. $50\%$
4. $100\%$

Q. At what external pressure will water boil ${140}^{\circ }C$? (S VP at ${140}^{\circ }C$ =2710 mmHg)

1. 2.53
2. 1
3. None
4. 3.56

Q. On a winter day, the outside temperature is $0^{\circ }C$ and relative humidity $40\%$. The air from outside comes into a room and is heated to ${20}^{\circ }C$. What is the relative humidity in the room ? The saturation vapour pressure at $0^{\circ }C$ is $4.6mm$ of mercury and at ${20}^{\circ }C$ it is $18mm$ of mercury.

Q. Nita is ready to go to her office. She wears gloves in hands and covers her eyes with
sunglass. Her daughter Meena asked her that why she she is wearing so many things
to cover her body as atmosphere is protecting us but Nita said that the present situation is not so good.
Now answer the question.
Why Nita has said so?
Do you agree with Nitas thought?
Give reason for your answer.?

Q. Explain why the climate of a harbour town is more temperature than that of a town in a desert at the same latitude.

Q. At ___________, relative humidity is 100%.

1. boiling point
2. melting point
3. dew point
4. freezing point

Q. The condition of air in a closed room is described as follows. Temperature $={25}^{\circ }C$, relative humidity $=60\%$ , pressure $=104kPa$. If all the water vapour is removed, from the room without changing the temperature, what will be the new pressure? The saturation vapour pressure at ${25}^{\circ }C=3.2kPa$

Q. The relative humidity is $50\%$, if the air contains about :

1. $2.55g$ of water vapour at ${40}^{\circ }C$
2. $25.5g$ of water vapour at ${40}^{\circ }C$
3. $2.55kg$ of water vapour at ${40}^{\circ }C$
4. $25.5kg$ of water vapour at ${40}^{\circ }C$