Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
Reynolds number (RN) is given by (where h = Film coefficient, l = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, ? = Density of fluid, cp = Specific heat at constant pressure, and ? = Coefficient of absolute viscosity)
Options- A.
- B.
- C.
- D.
- Correct Answer
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- 1. Thermal diffusivity is a
Options- A. function of temperature
- B. physical property of a substance
- C. dimensionless parameter
- D. all of these Discuss
- 2. The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is
Options- A. equal to one
- B. greater than one
- C. less than one
- D. equal to Nusselt number Discuss
- 3. The highest thermal diffusivity is of
Options- A. iron
- B. lead
- C. concrete
- D. wood Discuss
- 4. The C.O.P. of an absorption type refrigerator is given by (where T1 = Temperature at which the working substance receives heat, T2 = Temperature of cooling water, and T3 = Evaporator temperature)
Options- A.
- B.
- C.
- D.
Discuss
- 5. The heat transfer by radiation __________ a medium.
Options- A. requires
- B. does not require Discuss
- 6. Thermal conductivity of water __________ with rise in temperature.
Options- A. remains same
- B. decreases
- C. increases
- D. may increase or decrease depending upon temperature Discuss
- 7. A refrigeration system
Options- A. removes heat from a low temperature body and delivers it to a high temperature body
- B. removes heat from a high temperature body and delivers it to a low temperature body
- C. rejects energy to a low temperature body
- D. none of the above Discuss
- 8. A perfect black body is one which
Options- A. is black in colour
- B. absorbs heat radiations of all wave lengths falling on it
- C. reflects all the heat radiations
- D. transmits the heat radiations Discuss
- 9. While designing the refrigeration system of an aircraft, the prime consideration is that the
Options- A. system has high C.O.P.
- B. power per TR is low
- C. mass of refrigerant circulated in the system is low
- D. mass of the refrigeration equipment is low Discuss
- 10. The difference between dry bulb temperature and wet bulb temperature, is called
Options- A. dry bulb depression
- B. wet bulb depression
- C. dew point depression
- D. degree of saturation Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: physical property of a substance
Correct Answer: equal to one
Correct Answer: lead
Correct Answer:
Correct Answer: does not require
Correct Answer: may increase or decrease depending upon temperature
Correct Answer: removes heat from a low temperature body and delivers it to a high temperature body
Correct Answer: absorbs heat radiations of all wave lengths falling on it
Correct Answer: mass of the refrigeration equipment is low
Correct Answer: wet bulb depression
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