The boiling point of ________ is 10.5°C.
Ammonia
R-12
Sulphur dioxide
Carbon dioxide
Correct Answer :
C. Sulphur dioxide
Related Questions
During heating and humidification, the final relative humidity of 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
The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure, is called
Humidity ratio
Relative humidity
Absolute humidity
Degree of saturation
The operating temperature of a cold storage is 2°C. The heat leakage from the surrounding is 30 kW for the ambient temperature of 40°C. The actual C.O.P. of refrigeration plant used is one fourth that of ideal plant working between the same temperatures. The power required to drive the plant is
1.86 kW
3.72 kW
7.44 kW
18.6 kW
The thermostatic expansion valve is used in __________ type of evaporators.
Flooded
DX coil
Dry
None of these
Chaperon equation is applicable for registration at
Saturation point of vapour
Saturation point of liquid
Sublimation temperature
Triple point
For better C.O.P of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be
Small
High
Equal
Anything
The human body feels comfortable when the heat stored in the body is
Positive
Negative
Zero
None of these
The domestic refrigerator uses following type of compressor
Centrifugal
Axial
Miniature sealed unit
Piston type reciprocating
The superheated vapour region, in a pressure enthalpy chart, is represented by the space
To the left of saturated liquid line
To the right of saturated liquid line
Between the saturated liquid line and saturated vapour line
None of the above
One of the purposes of sub cooling the liquid refrigerant is to
Reduce compressor overheating
Reduce compressor discharge temperature
Increase cooling effect
Ensure that only liquid and not the vapour enters the expansion (throttling) valve
The boiling point of carbon dioxide is
-20.5°C
-50°C
-63.3°C
-78.3°C
In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = Bypass factor)
B.P.F. - 1
1 - B. P.F.
1/ B.P.F.
1 + B.P.F.
The fluids used in Electrolux refrigerator are
Water and hydrogen
Ammonia and hydrogen
Ammonia, water and hydrogen
None of these
Which of the following statement is wrong?
The value of C.O.P. is always greater than one.
In a vapour compression system, the condition of refrigerant before entering the compressor is dry saturated vapour.
The space between the saturated liquid line and saturated vapour line, in a pressure enthalpy chart, is wet vapour region.
None of the above
The bank of tubes at the back of domestic refrigerator is
Condenser tubes
Evaporator tubes
Refrigerant cooling tubes
Capillary tubes
In a saturated air-water vapour mixture, the
Dry bulb temperature is higher than wet bulb temperature
Dew point temperature is lower than wet bulb temperature
Dry bulb, wet bulb and dew point temperature are same
Dry bulb temperature is higher than dew point temperature
The difference between dry bulb temperature and wet bulb temperature, is called
Dry bulb depression
Wet bulb depression
Dew point depression
Degree of saturation
When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be
Cooled and humidified
Cooled and dehumidified
Heated and humidified
Heated and dehumidified
For obtaining high COP, the pressure range of compressor should be
High
Low
Optimum
Any value
In actual air-conditioning applications for R-12 and R-22, and operating at a condenser temperature of 40° C and an evaporator temperature of 5° C, the heat rejection factor is about
1
1.25
2.15
5.12
A valve which maintains a constant degree of superheat at the end of the evaporator coil, is called
Automatic expansion valve
High side float valve
Thermostatic expansion valve
Low side float valve
During humidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant
Decreases
Increases
Remain same
Depends on other factors
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 bypass factor of the heating coil is
0.376
0.4
0.6
0.67
The wet bulb temperature during sensible heating of air
Remains constant
Increases
Decreases
None of these
The C.O.P. of a Carnot refrigerator in winter will be _________ as compared to C.O.P. in summer.
Same
Lower
Higher
None of these
A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
Lack of cooling water
Water temperature being high
Dirty condenser surface
All of these
The coefficient of performance of Electrolux refrigerator is the ratio of
Heat supplied by the gas burner to the heat absorbed by the evaporator
Heat absorbed by the evaporator to the heat supplied by the gas burner
Heat supplied by the gas burner minus the heat absorbed by the evaporator to the heat supplied by the gas burner
Heat absorbed by the evaporator minus the heat supplied by the gas burner to the heat absorbed by the evaporator
The wet bulb temperature at 100% relative humidity is ________ dry bulb temperature.
Same as
Lower than
Higher than
None of these
During a refrigeration cycle, heat is rejected by the refrigerant in a
Compressor
Condenser
Evaporator
Expansion valve