Chapter 10

Question 1

Relative humidity is the amount of _____ expressed as a percentage.
Select one:

A.
Moisture contained in the air compared to the maximum amount of moisture the air is capable of holding at any temperature

B.
Air contained in the moisture compared to the minimum amount of moisture the air is capable of holding at the stated temperature

C.
Moisture contained in the air compared to the minimum amount of moisture the air is capable of holding at the stated temperature

D.
Air contained in the moisture compared to the maximum amount of moisture the air is capable of holding at the stated temperature

E.
Moisture contained in the air compared to the maximum amount of moisture the air is capable of holding at the stated temperature

Answer 1

E.
Moisture contained in the air compared to the maximum amount of moisture the air is capable of holding at the stated temperature

Question 2

When the air temperature is raised without a change in moisture content the relative humidity will:
Select one:

A.
Not change

B.
Decrease

C.
Lose latent heat

D.
Gain latent heat

E.
Increase

Answer 2

B.
Decrease

Question 3

Calculate the relative humidity of a sample of air that at 21°C (70°F) holds 0.005 kg (0.011 lb) of moisture if the maximum that it can hold at this temperature is 0.015 kg (0.033 lb).
Select one:

A.
10.7%

B.
93.3%

C.
25.8%

D.
6.7%

E.
0.33%

Answer 3

E.
0.33%

Question 4

One of the wetted element humidifiers group is the _____ type.
Select one:

A.
Pan

B.
Steam

C.
Spray

D.
Wet

E.
Bypass

Answer 4

E.
Bypass

Question 5

One of the types of humidifiers used for residential purposes is the _____ humidifier.
Select one:

A.
Pot

B.
Dry element

C.
Wetted element

D.
Air washer

E.
Steam

Answer 5

C.
Wetted element

Question 6

An air washer is installed on the suction side of the fan so as to:
Select one:

A.
Avoid leakage of air through the joints

B.
Add latent heat to the air

C.
Add moisture to the air

D.
Avoid leakage of water through the joints

E.
Add sensible heat to the air

Answer 6

D.
Avoid leakage of water through the joints

Question 7

Calculate the relative humidity of a sample of air that at 21°C (70°F) holds 0.014 kg (0.031 lb) of moisture if the maximum that it can hold at this temperature is 0.015 kg (0.033 lb).
Select one:

A.
25.8%

B.
6.7%

C.
0.33%

D.
93.3%

E.
10.7%

Answer 7

D.
93.3%

Question 8

Calculate the relative humidity of a sample of air that at 21°C (70°F) holds 0.01 kg (0.022 lb) of moisture if the maximum that it can hold at this temperature is 0.015 kg (0.033 lb).
Select one:

A.
10.7%

B.
93.3%

C.
0.33%

D.
25.8%

E.
66.7%

Answer 8

E.
66.7%

Question 9

When the air temperature is lowered without a change in moisture content the relative humidity will:
Select one:

A.
Gain latent heat

B.
Decrease

C.
Not change

D.
Increase

E.
Lose latent heat

Answer 9

D.
Increase

Question 10

One of the types of humidifiers used for residential purposes is the _____ humidifier.
Select one:

A.
Pan

B.
Steam

C.
Air washer

D.
Pot

E.
Dry element

Answer 10

A.
Pan

Question 11

The steam pressure on a steam grid humidifier should be in the range of:
Select one:

A.
25 kPa to 45 kPa (3.6 to 6.5 psi)

B.
40 kPa to 55 kPa (5.8 to 8 psi)

C.
30 kPa to 60 kPa (4.4 to 8.7 psi)

D.
35 kPa to 70 kPa (5.1 to 10.2 psi)

E.
20 kPa to 30 kPa (2.9 to 4.4 psi)

Answer 11

D.
35 kPa to 70 kPa (5.1 to 10.2 psi)

Question 12

From a health standpoint, humidity between _____ is desirable.
Select one:

A.
45% and 60%

B.
55% and 80%

C.
35% and 50%

D.
25% and 40%

E.
15% and 30%

Answer 12

C. 35% and 50%

Question 13

When the air washer is used for humidification, the spray water must be _____ temperature of the entering air.
Select one:

A.
Heated above the dew point

B.
Cooled below the wet bulb

C.
Cooled below the dew point

D.
Cooled below the dry bulb

E.
Heated above the dry bulb

Answer 13

A.
Heated above the dew point

Question 14

The steam heated pan humidifier offers high capacity and accurate humidity control if used with a modulating control valve and steam pressure not exceeding:
Select one:

A.
160 kPa (23.2 psi)

B.
50 kPa (7.3 psi)

C.
103 kPa (15 psi)

D.
10 kPa (1.5 psi)

E.
130 kPa (19 psi)

Answer 14

C.
103 kPa (15 psi)

Question 15

Calculate the relative humidity of a sample of air that at 21°C (70°F) holds 0.01 kg (0.022 lb) of moisture if the maximum that it can hold at this temperature is 0.015 kg (0.033 lb).
Select one:

A.
10.7%

B.
25.8%

C.
93.3%

D.
0.33%

E.
6.7%

Answer 15

E.
6.7%

Question 16

One of the wetted element humidifiers group is the _____ type.
Select one:

A.
Wet

B.
Steam

C.
Pan

D.
Spray

E.
Power

Answer 16

E.
Power

Question 17

The humidification process refers to adding _____ to the air.
Select one:

A.
Water vapour or moisture

B.
Heat

C.
Temperature

D.
Steam

E.
Enthalpy

Answer 17

A.
Water vapour or moisture

Question 18

Atomizing humidifiers have the disadvantage that:
Select one:

A.
They have no moving parts

B.
They do not require a motor

C.
They add moisture to the air

D.
The water sprayed into the air evaporates leaving the salts that appear as a fine white dust

E.
They have no float valve

Answer 18

D.
The water sprayed into the air evaporates leaving the salts that appear as a fine white dust

Question 19

One of the types of humidifiers used for residential purposes is the _____ humidifier.
Select one:

A.
Atomizing

B.
Steam

C.
Air washer

D.
Pot

E.
Dry element

Answer 19

A.
Atomizing

Question 20

The pan type humidifier has a/an:
Select one:

A.
Low humidification rate

B.
Very High humidification rate

C.
High humidification rate

D.
Moderate humidification rate

E.
Very low humidification rate

Answer 20

E.
Very low humidification rate

Question 21

When the air washer is used for dehumidification, the spray water must be _____ temperature of the entering air.
Select one:

A.
Cooled below the dew point

B.
Heated above the dry bulb

C.
Heated above the dew point

D.
Cooled below the dry bulb

E.
Cooled below the wet bulb

Answer 21

A.
Cooled below the dew point