Chapter 35 Review Questions
Which of the following is a correct formula for total heat?
QT = QS + QL
What is the dew point temperature of a 75°F air sample with a relative humidity of 60%?
60°F
Air is primarily made up of
78% nitrogen, 21% oxygen.
The term enthalpy applies to
a combination of latent heat and sensible heat.
The body gives off heat in all of the following ways except
condensation.
At standard atmospheric pressure, air has a density of
0.075 lb/ft3.
Multiplying the density of a gas and its specific volume together will always produce a result equal to
1.
Enthalpy is expressed in which of the following units?
Btu/lb
In a cooling-only process, all of the following are true except
the absolute humidity drops.
If only the absolute humidity of an air sample is known, which of the following values can be determined from the psychrometric chart?
wet-bulb temperature
If the wet-bulb depression is 0°F, what is the relative humidity of the air sample?
100%
The nitrogen and oxygen in our air are classified as
superheated gases.
On the psychrometric chart, the scale along the bottom of the chart represents
dry-bulb temperature.
Relative humidity is measured using which of the following instruments?
psychrometer
Air that contains all of the moisture that it can hold is referred to as being
saturated.
If the dry-bulb temperature is 75°F and the wet-bulb temperature is 60°F, the wet-bulb depression is
15°F.
In order for an evaporator to remove moisture from the airstream passing through it, the evaporator coil must be at a temperature that is lower than the air's
dew point temperature.
Of the following sets of air properties, which two can be identified by following the same line?
enthalpy and wet-bulb temperature
If the density of a gas is 0.5 lb/ft3, what is its specific volume?
2 ft3/lb
Which of the following statements is true regarding the heating of an air sample?
The relative humidity will drop and the absolute humidity will remain the same.
If an air sample holds 60 grains of moisture (per pound) and has the ability to hold a maximum of 90 grains of moisture (per pound), what is the relative humidity of the air sample?
67%
According to the winter comfort chart, Figure 35.6(B), people will generally be comfortable when exposed to which of the following sets of conditions?
70°F at 50% relative humidity
According to the summer comfort chart, Figure 35.6(A), people will generally be comfortable when exposed to which of the following sets of conditions?
75°F at 50% relative humidity
If the human body is exposed to very warm temperatures, which of the following is true?
Perspiration will form to cool the body.
Which of the following is true regarding wet-bulb and dry-bulb temperatures?
The wet-bulb temperature reading can be equal to the dry-bulb temperature reading.
Condensate dripping from an air-conditioning system is an indication that the evaporator coil temperature is
cooler than the air's dew point temperature.
In the winter, lower room temperatures can be offset by
increasing the relative humidity.
The term used to describe the random air that leaks into a structure is
infiltration.
