Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is __________ that for counter flow.
Options- A. equal to
- B. less than
- C. greater than
- Correct Answer
- equal to
- 1. The automobile radiator is a heat exchanger of
Options- A. parallel flow type
- B. counter flow type
- C. cross flow type
- D. regenerator type Discuss
- 2. The wave length corresponding to the maximum energy is inversely proportional to the absolute temperature. This statement is called Planck's law.
Options- A. Yes
- B. No Discuss
- 3. A vapour absorption refrigerator uses __________ as a refrigerant.
Options- A. water
- B. ammonia
- C. freon
- D. aqua-ammonia Discuss
- 4. The material of pipe lines for a system using ammonia as a refrigerant should be copper.
Options- A. Yes
- B. No Discuss
- 5. The curved lines on a psychrometric chart indicates
Options- A. dry bulb temperature
- B. wet bulb temperature
- C. dew point temperature
- D. relative humidity Discuss
- 6. For a white body, absorptivity (? ) = 0, reflectivity (?) = 1 and transmittivity (?) = 0.
Options- A. Correct
- B. Incorrect Discuss
- 7. The use of heat exchangers is made in
Options- A. radiators in automobile
- B. condensers and boilers in steam plants
- C. condensers and evaporators in refrigeration and air conditioning units
- D. all of the above Discuss
- 8. The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is equal to
Options- A. -1/3
- B. -2/3
- C. 1
- D. -1 Discuss
- 9. The sensible heat factor during the heating and humidification process is given by (where h1 = Enthalpy of air entering the heating coil, h2 = Enthalpy of air leaving the heating coil, and hA = Enthalpy of air at the end of humidification process)
Options- A.
- B.
- C.
- D.
Discuss
- 10. The horizontal and uniformly spaced lines on a psychrometric chart indicates relative humidity.
Options- A. Correct
- B. Incorrect Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: cross flow type
Correct Answer: No
Correct Answer: aqua-ammonia
Correct Answer: No
Correct Answer: relative humidity
Correct Answer: Correct
Correct Answer: all of the above
Correct Answer: -1/3
Correct Answer:
Correct Answer: Incorrect
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