Online Blended Learning Activity CHP 10

What is the difference between dry air and atmospheric air?

• Dry air does not contain any water vapor, but atmospheric air does.
• Atmospheric does not contain any water vapor, but dry air does.

Which of the following statement on humidity is TRUE?

• Same amount of water vapor results in higher humidity in warm air than cold air

• Humidity is the concentration of water vapour present in the air, depend on temperature & pressure

Relative humidity is the amount of water vapor present in a unit mass of dry air. Specific humidity is the ratio of the actual amount of vapor in the air at a given temperature to the maximum amount of vapor air can hold at that temperature

• TRUE
• FALSE

What is the different between dry bulb and wet bulb temperature?

• Dry bulb is the air temperature whereas wet bulb is the saturation temperature of the air at a constant pressure condition.
• Dry bulb is the saturation temperature of the air at a constant pressure condition whereas wet bulb temperature is the air temperature

Which of the following statement is TRUE?

• Relative humidity ranges from 1 for dry air to 0 for saturated air
• The enthalpy of atmospheric air is expressed per unit mass of dry air instead of per unit mass of the air–water vapor mixture
• At 100% relative humidity, the wet-bulb temperature is difference from air temperature

• Dew point temperature is the temperature at which condensation begins when the air is heated at constant pressure.

Which of the following statement on the relative humidity change during simple heating or cooling with constant ω (specific humidity) is TRUE?

• the relative humidity will increase when the cooling process occurred and decrease when the heating process occurred

• the relative humidity will decrease when the cooling process occurred and will increase when the heating process occurred

Simple heating can result low relative humidity of air. This problem can be eliminated by humidifying the heated air.

• TRUE
• FALSE

It may be necessary to add some moisture by dehumidify it when the relative humidity is low

• TRUE
• FALSE

Which of the following statement is FALSE?

• 
  Adiabatic saturation is the temperature at which water will saturate air by evaporating adiabatically into it. 

• Wet bulb temperature is the highest temperature that air can be cooled by the evaporation of water into the air at a constant pressure

• Saturated air is the condition where the air is saturated with moisture.

• During adiabatic saturation process, the moisture content of air increases and its temperature decreases

Why the liquid droplet appeared on the cold drink tin?

• the temperature of the cold drink higher than the air temperature

• the temperature of air lower than the temperature of cold drink

• the temperature of the cold drink lower than the dew temperature of air

• the temperature of the cold drink higher than the dew temperature of air