REFRIGERATION & AIR CONDITIONING
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Xem trước 25/50 câu hỏi trong đề. Bấm Vào thi để làm bài trực tuyến, được chấm điểm và xem đáp án chi tiết.
Câu 1. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. The refrigerant used in car air conditioning is
- A. None
- B. R-134a
- C. Ammonia
- D. R-22
Câu 2. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In comfort air conditioning, room air and ventilation air are in the ratio
- A. 60 : 40
- B. 40:60
- C. None
- D. 80 : 20
Câu 3. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. The material of pipe lines for a system using Freon as a refrigerant should be
- A. Steel
- B. Copper
- C. Aluminum
- D. Brass
Câu 4. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In operation theatres of comfort air conditioning, the ratio of room air and ventilation air is
- A. 50 : 50
- B. 100 : 0
- C. 0:100
- D. None of these
Câu 5. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. Summer air conditioning means
- A. None
- B. Cooling, humidification& dehumidification
- C. Cooling & dehumidification
- D. Cooling & humidification
Câu 6. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. The COP of a vapour compression plant in comparison to vapour absorption plant is
- A. More
- B. More/less depending on size of plant
- C. Less
- D. Same
Câu 7. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is
- A. Smaller
- B. Smaller/bigger depending on capacity
- C. Equal
- D. Bigger
Câu 8. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. When detecting a lack of refrigerant, what should be done immediately?
- A. Recharge refrigerant immediately
- B. Adjust the setting temperature
- C. Find down the cause of refrigerant loss
- D. No need to do anything
Câu 9. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In a vapour compression system, the condition of refrigerant before passing through the condenser is
- A. Wet vapour
- B. Superheated vapour
- C. Saturated liquid
- D. Dry saturated vapour
Câu 10. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. Which method is commonly used to detect defects in tube-type heat exchangers?
- A. None of these
- B. Hydraulic test with a pressure about 2 times the working pressure
- C. Using radiation test
- D. Hydraulic test with a pressure of about 1.5 times the working pressure
Câu 11. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. Formation of frost on evaporator in refrigerator
- A. Can be avoided by proper design
- B. Increases heat transfer rate
- C. Is immaterial
- D. Results in loss of heat due to poor heat transfer
Câu 12. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. The evaporator changes the low pressure liquid refrigerant from the expansion valve into
- A. Low pressure liquid and vapour refrigerant
- B. Low pressure vapour refrigerant
- C. High pressure liquid refrigerant
- D. None of these
Câu 13. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In a vapour compression cycle, the refrigerant immediately after expansion valve is
- A. Saturated liquid
- B. Liquid
- C. Wet vapour
- D. Sub-cooled liquid
Câu 14. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. An important characteristic of absorption system of refrigeration is
- A. Cooling below 0°C
- B. Noisy operation
- C. Quiet operation
- D. Very little power consumption
Câu 15. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In a vapour compression refrigeration system, a throttle valve is used in place of an expander because
- A. It leads to significant cost reduction
- B. It improves the C.O.P., as the condenser is small
- C. The positive work in isentropic expansion of liquid is very small
- D. It considerably reduces mass of the system
Câu 16. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. Environmental protection agencies advice against the use of chlorofluorocarbon refrigerants since
- A. These react with plants and cause greenhouse effect
- B. These react with oxygen and cause its depletion
- C. These react with ozone layer
- D. These react with water vapour and cause acid rain
Câu 17. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. Which of the following does not reduce lubricating oil pressure?
- A. Lack of refrigerant
- B. Low oil level or/and dirty filter
- C. Excess refrigerant
- D. High oil temperature, poor quality oil, bearing clearance exceeds the allowable limit
Câu 18. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In air conditioning, types of loads added are
- A. Sensible heat loads
- B. Latent heat loads
- C. Both sensible & latent heat loads
- D. None
Câu 19. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In a mixing type heat exchanger, there is a simultaneous conversion of
- A. Volume
- B. None of these
- C. Heat and mass
- D. Heat
Câu 20. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. Which of the following appearances shows that the evaporator is covered with too much snow and ice?
- A. The compressor is flooded with ice and snow all the way to the compressor
- B. All of these occur simultaneously
- C. Discharge temperature is less than 60 degrees Celsius
- D. Suction pressure decreases
Câu 21. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow. In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to
- A. Detect liquid in vapour
- B. Collect liquid refrigerant and prevent it from going to compressor
- C. Superheat the vapour
- D. Collect vapors
Câu 22. 50 MULTIPLE-CHOICE QUESTIONS Correct answers are highlighted in yellow.
- A. refrigerant compressor is used to
- B. Circulate the refrigerant through the refrigerating system
- C. Raise the pressure of the refrigerant
- D. All of these
Câu 23. D. Raise the temperature of the refrigerant Pick up the wrong statement. A refrigerant should have
- A. Tow specific heat of liquid
- B. Higher critical temperature
- C. High latent heat of vaporization
- D. High boiling point
Câu 24. D. Raise the temperature of the refrigerant If a gas is to be liquefied, its temperature must be
- A. None of these
- B. Increased to a value above its critical temperature
- C. Reduced to a value below its critical temperature
- D. Equal to critical temperature
Câu 25. D. Raise the temperature of the refrigerant Air refrigerator works on
- A. Reversed Carnot and Bell Coleman cycle
- B. Bell Coleman cycle
- C. Reversed Carnot cycle
- D. None of these
… và còn 25 câu nữa. Bấm Vào thi phía trên để làm toàn bộ 50 câu và xem đáp án.
