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WorksheetsPSYCHROMETRICS
Total questions: 37
Worksheet time: 19mins
For unsaturated air, the dew point temperature is __________ wet bulb temperature.
equal to
less than
more than
can’t predict
The wet bulb depression indicates __________ humidity of the air.
absolute
relative
specific
any of the above
The wet-bulb depression is zero when relative humidity is
0%
50%
75%
100%
The minimum temperature to which water can be cooled in a cooling tower is
dew point temperature of air
wet bulb temperature of air
dry bulb temperature of air
ambient air temperature
A low wet bulb temperature indicates very __________ humidity.
low
high
can’t predict
100%
The wet bulb temperature at 100% relative humidity is __________ dew point temperature.
same as
lower than
higher than
may lower or higher
The sensible cooling process on the psychrometric chart is shown by
horizontal line
vertical line
inclined line
curved
During sensible cooling of air __________remains constant.
dew point temperature
specific humidity
dry bulb temperature
both A and B
The dry bulb temperature during sensible cooling of air
remains constant
increases
decreases
first increases then decreases
Which of the following statement is TRUE?
During sensible cooling of the air, both dry bulb and wet bulb temperatures decrease
During sensible cooling of the air, dry bulb temperature decreases but wet bulb temperature remains constant
During sensible cooling of the air, dry and wet bulb temperatures decrease but dew point temperature remains constant
Both A and C
In case of sensible cooling of air, the coil efficiency is given by (where BPF = by-pass-factor)
BPF - 1
1 - BPF
BPF
1 + BPF
When BPF of the cooling coil is 0.3, then its efficiency will be
0
1
0.7
0.5
The by-pass factor of a cooling coil decreases with
decrease in fin spacing and increase in number of rows
increase in fin spacing and increase in number of rows
increase in fin spacing and decrease in number of rows
decrease in fin spacing and decrease in number of rows
The by-pass factor for a cooling coil
increases with increase in velocity of air passing through it
decreases with increase in velocity of air passing through it
remains unchanged with increase in velocity of air passing through it
may increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering
The wet bulb temperature during sensible heating of air
remains constant
increases
decreases
first increases then decrease
The atmospheric air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The by-pass factor of the heating coil is
0.376
0.4
0.6
0.67
The humidification process on the psychrometric chart is shown by
horizontal line
vertical line
inclined line
curved
During humidification process __________ remains constant.
relative humidity
dry bulb temperature
dew point temperature
wet bulb temperature
The specific humidity during dehumidification process
remains constant
increases
decreases
first increases then decreases
The moisture content during cooling and dehumidification process
remains constant
decreases
increases
none of these
In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature
which lies between the dry bulb and wet bulb temperatures of the incoming stream
which lies between the wet bulb and dew point temperatures of the incoming stream
which is lower than the dew point temperature of the incoming stream
of adiabatic saturation of incoming stream
It is desired to condition the outside air from 70% relative humidity and 45°C dry bulb temperature to 50% relative humidity and 25°C dry bulb temperature (room condition). The practical arrangement will be
dehumidification
cooling and humidification
cooling and dehumidification
dehumidification and pure sensible cooling
The relative humidity __________ as air gets drier.
increases
decreases
remains constant
can’t predict
Sensible heat factor is given by (where S.H. = Sensible Heat and L.H. = Latent Heat)
S.H/(S.H + L.H)
(S.H + L.H) /S.H
(L.H - S.H)/S.H
S.H/(L.H - S.H)
If sensible heat factor zero, then it indicates
no sensible heat transfer
no latent heat transfer
both sensible and latent heat transfer
neither sensible nor latent heat transfer
Sensible heat factor during pure sensible cooling is
0
0.5
1
between 0 to 1
In a psychrometric process, the sensible heat added is 30 kJ/s and the latent heat added is 20 kJ/s. The sensible heat factor for the process will be
0.3
0.4
0.6
0.8
Which of the following statement is TRUE?
During cooling and humidification process, the enthalpy of air decreases
During cooling and humidification process, the enthalpy of air increases
During cooling and humidification process, the enthalpy of air remains constant
During cooling and humidification process, the enthalpy of air may increase, decrease or remain constant depending upon the temperature of the wet surface
The psychrometric process used in air cooler is
cooling and dehumidification
heating and humidification
cooling and humidification
heating and dehumidification
The evaporative cooling systems are
environment friendly
offer lower initial and lower running cost
easier to maintain and fabricate
all of the above
Which of the following psychrometric process used in the cooling tower?
Heating and dehumidification
Heating and humidification
Cooling and dehumidification
Cooling and humidification
During adiabatic saturation process on unsaturated air __________ remains constant.
relative humidity
dew point temperature
dry bulb temperature
wet bulb temperature
The specific humidity during heating and humidification process
remains constant
increases
decreases
remains constant
In an air washer system, if the temperature of the spraying water is higher than the dry bulb temperature of entering air, then the air is
heated and dehumidified
heated and humidified
cooled and humidified
cooled and dehumidified
During heating and humidification, the final relative humidity of the air
can be lower or higher than that of the entering air
is lower than that of the entering air
is higher than that of the entering air
none of the above
In chemical dehumidification process
dew point temperature decreases
wet bulb temperature decreases
dry bulb temperature increases
all of these
An air washer can work as a
humidifier
dehumidifier
filter
all of the above
