AIR CONDITIONING MCQ question and answers

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AIR CONDITIONING MCQ question and answers

1. The dry bulb temperature lines are
(a) parallel, equispaced
(b) inclined, parallel and equispaced
(c) inclined, parallel and non-equispaced
(d) vertical and parallel to each other

2. The dew-point temperature lines are
(a) parallel, equispaced
(b) inclined, parallel and equispaced
(c) inclined, parallel and non-equispaced
(d) horizontal, equispaced and parallel to each other

3. The specific volume lines are
(a) parallel, equispaced
(b) inclined, parallel and equispaced
(c) inclined, parallel and non-equispaced
(d) horizontal, equi-spaced and parallel to each other

4. The compressors used in refrigerator system are of
(a) hermatically sealed type
(b) vane type
(c) centrifugal type
(d) reciprocating type

5. In humidification process the humidity increases and the DBT
(a) increases
(b) decreases
(c) same
(d) first rise then decrease

6. In sensible cooling the specific humidity
(a) increases
(b) decreases
(c) same
(d) first rise then decrease

7. In sensible cooling the DBT of air
(a) increases
(b) decreases
(c) same
(d) first rise then decrease

8. In dehumidification process the humidity increases and the DBT
(a) increases
(b) decreases
(c) same
(d) first rise then decrease

9. In chemical humidification the enthalpy of air
(a) increases
(b) decreases
(c) same
(d) first rise then decrease

10. The bulb of psychrometer is dry then it will indicate
(a) DPT
(b) DBT
(c) WBT
(d) dry bulb depression

11. If the bulb of psychrometer is surrounded by a wet wick then it will give value of
(a) DPT
(b) DBT
(c) WBT
(d) dry bulb depression

12. The Wet bulb depression is zero when Relative humidity equals
(a) 0
(b) 0.5
(c) 0.75
(d) 1

13. In a psychrometric chart, the vertical lines parallel to the ordinate indicate
(a) Dry bulb Temperature
(b) Wet bulb Temperature
(c) Specific humidity
(d) Enthalpy of saturation

14. The uniformly spaced horizontal lines running parallel to the abscissa in a psychrometric chart indicate
(a) Absolute humidity
(b) Specific humidity
(c) Dew point temperature
(d) Volume

15. Which of the following statements are TRUE?
(a) Thermodynamic WBT is a property of moist air, while WBT asmeasured by wet bulb thermometer is not a property
(b) Both the thermodynamic WBT and WBT as measured by wet bulb thermometer are properties of moist air
(c) Under no circumstances, dry bulb and wet bulb temperatures are equal
(d) Wet bulb temperature is always lower than dry bulb temperature, but higher than dew point temperature

16. Which of the following statements are TRUE?
(a) During sensible cooling of air, both dry bulb and wet bulb temperatures decrease
(b) During sensible cooling of air, dry bulb temperature decreases but wet bulb temperature remains constant
(c) During sensible cooling of air, dry and wet bulb temperatures decrease but dew point temperature remains constant
(d) During sensible cooling of air, dry bulb, wet bulb and dew point temperatures decrease

17. Which of the following statements are TRUE?
(a) During cooling and humidification process, the enthalpy of air decreases
(b) During cooling and humidification process, the enthalpy of air increases
(c) During cooling and humidification process, the enthalpy of air remains constant
(d) During cooling and humidification process, the enthalpy of air may increase, decrease or remain constant depending upon the temperature of the wet surface

18. The temperature at which the water vapour in the air starts condensing is known as
(a) dew point
(b) dry bulb
(c) wet bulb
(d) saturation

19. When moisture is added to air at constant dry bulb temperature, the process is known as
(a) Sensible cooling
(b) humidification
(c) dehumidification
(d) Chilling

20. Which of the following can be measured by a sling psychrometer?
(a) Wet bulb temperature
(b) Dry bulb as well as wet bulb temperatures
(c) Specific humidity
(d) Absolute humidity

21. A mixture of dry air and water vapour, when the air has diffused the maximum amount of water vapour into it, is called
(a) Dry air
(b) Moist air
(c) Saturated air
(d) Specific humidity

22. The temperature of air recorded by a thermometer, when it is not effected by the moisture present in it, is called
(a) Wet bulb temperature
(b) Dry bulb temperature
(c) Dew point temperature
(d) None of these

23. The relative humidity of air is defined as the ratio of
(a) Mass of water vapour in a given volume to the total mass of the mixture of air and water vapour.
(b) Mass of water vapour in a given volume to the mass of water vapour, if air is saturated at the same temperature
(c) Mass of water vapour in a given volume to the mass of air
(d) Mass of air to the mass of water vapour in the mixture of air and water vapour

24. On a psychrometric chart, sensible cooling is represented by
(a) Horizontal line
(b) Inclined line
(c) Vertical line
(d) None of these

25. If relative humidity is 100% , then
(a) Dry bulb temperature is greater than wet bulb temperature
(b) Wet bulb temperature is greater than dry bulb temperature
(c) Dry bulb temperature is equal to wet bulb temperature
(d) Dry bulb temperature is one-half of wet bulb temperature

26. The curved lines on a psychrometric chart indicates
(a) Dry bulb temperature
(b) Wet bulb temperature
(c) Specific humidity
(d) Relative humidity

26. The minimum temperature to which moist air can be cooled under ideal conditions in a spray washer is
(e) Dew point temperature of inlet air
(f) Wet bulb temperature of inlet air
(g) Water inlet temperature
(h) Water outlet temperature