Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
The __________ point of ammonia is -77.7°C.
Options- A. freezing
- B. boiling
- Correct Answer
- freezing
- 1. The value of the wave length for maximum emissive power is given by
Options- A. Kirchhoff's law
- B. Stefan's law
- C. Wein's law
- D. Planck's law Discuss
- 2. A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100° C and leaves at 60° C. A cold fluid enters the heat exchanger at 40° C. The mean temperature difference between the two fluids is
Options- A. 20°C
- B. 40°C
- C. 60°C
- D. 66.7°C Discuss
- 3. The relative humidity lines on a psychrometric chart are
Options- A. vertical and uniformly spaced
- B. horizontal and uniformly spaced
- C. horizontal and non-uniformly spaced
- D. curved lines Discuss
- 4. A vapour absorption refrigeration system
Options- A. gives noisy operation
- B. gives quiet operation
- C. requires little power consumption
- D. cools below 0° C Discuss
- 5. Wet bulb temperature indicates the moisture content in air.
Options- A. Agree
- B. Disagree Discuss
- 6. Environmental protection agencies advice against the use of chloro-fluoro-carbon refrigerants since
Options- A. these react with water vapour and cause acid rain
- B. these react with plants and cause green-house effect
- C. these react with oxygen and cause its depletion
- D. these react with ozone layer Discuss
- 7. The heat is transferred by conduction, convection and radiation in
Options- A. melting of ice
- B. boiler furnaces
- C. condensation of steam in condenser
- D. none of these Discuss
- 8. The by-pass factor of a cooling coil decreases with
Options- A. decrease in fin spacing and increase in number of rows
- B. increase in fin spacing and increase in number of rows
- C. increase in fin spacing and decrease in number of rows
- D. decrease in fin spacing and decrease in number of rows Discuss
- 9. The expansion valve in a refrigerator controls the flow of refrigerant.
Options- A. Correct
- B. Incorrect Discuss
- 10. Emissivity of a body will be equal to its absorptivity at all temperatures.
Options- A. Yes
- B. No Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: Wein's law
Correct Answer: 20°C
Correct Answer: curved lines
Correct Answer: gives quiet operation
Correct Answer: Agree
Correct Answer: these react with ozone layer
Correct Answer: boiler furnaces
Correct Answer: decrease in fin spacing and increase in number of rows
Correct Answer: Correct
Correct Answer: No
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