Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called
Options- A. First law of thermodynamics
- B. Newton's law of cooling
- C. Newton's law of heating
- D. Stefan's law
- Correct Answer
- Newton's law of cooling
- 1. 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
Options- A. dehumidification
- B. cooling and humidification
- C. cooling and dehumidification
- D. dehumidification and pure sensible cooling Discuss
- 2. The boiling point of R-12 is about - 30°C.
Options- A. True
- B. False Discuss
- 3. In a parallel flow heat exchanger, the rate of flow of heat and the rate of decrease of temperature are maximum.
Options- A. Yes
- B. No Discuss
- 4. The refrigerant after condensation process is cooled below the saturation temperature before throttling. Such a process is called
Options- A. sub-cooling or under-cooling
- B. super-cooling
- C. normal cooling
- D. none of these Discuss
- 5. The fluids used in electrolux refrigerator are
Options- A. water and hydrogen
- B. ammonia and hydrogen
- C. ammonia, water and hydrogen
- D. none of these Discuss
- 6. The absolute humidity is the mass of water vapour present in 1 m3 of dry air.
Options- A. Agree
- B. Disagree Discuss
- 7. In a lithium bromide absorption refrigeration system
Options- A. lithium bromide is used as a refrigerant and water as an absorbent
- B. water is used as a refrigerant and lithium bromide as an absorbent
- C. ammonia is used as a refrigerant and lithium bromide as an absorbent
- D. none of the above Discuss
- 8. The thermostatic expansion valve is also called
Options- A. constant pressure valve
- B. constant temperature valve
- C. constant superheat valve
- D. none of these Discuss
- 9. During sensible heating of air __________ decreases.
Options- A. wet bulb temperature
- B. relative humidity
- C. dry bulb temperature
- D. specific humidity Discuss
- 10. The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles due to difference of density caused by temperature of the particle is known as
Options- A. conduction
- B. free convection
- C. forced convection
- D. radiation Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: cooling and dehumidification
Correct Answer: True
Correct Answer: Yes
Correct Answer: sub-cooling or under-cooling
Correct Answer: ammonia, water and hydrogen
Correct Answer: Agree
Correct Answer: water is used as a refrigerant and lithium bromide as an absorbent
Correct Answer: constant superheat valve
Correct Answer: relative humidity
Correct Answer: free convection
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