31. While designing the refrigeration system of an aircraft, the prime consideration is that the
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
32. The heat transfer takes place according to
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. Kirchhoff’s law
33. An Electrolux refrigerator is called a __________ absorption system.
A. single fluid
B. two fluids
C. three fluids
34. The heat transfer by radiation __________ a medium.
A. requires
B. does not require
35. Thermal conductivity of water __________ with rise in temperature.
A. remains same
B. decreases
C. increases
D. may increase or decrease depending upon the temperature
36. During adiabatic saturation process on unsaturated air __________ remains constant.
A. relative humidity
B. dew point temperature
C. dry bulb temperature
D. wet bulb temperature
37. The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is
A. equal to one
B. greater than one
C. less than one
D. equal to Nusselt number
38. A perfect black body is one which
A. is black in color
B. absorbs heat radiations of all wavelengths falling on it
C. reflects all the heat radiations
D. transmits the heat radiations
39. Degree of saturation or percentage humidity is
A. the mass of water vapor present in 1 m3 of dry air
B. the mass of water vapor present in 1 kg of dry air
C. the ratio of the actual mass of water vapor in a unit mass of dry air to the mass of water vapor in the same mass of dry air when it is saturated at the same temperature and pressure.
D. the ratio of the actual mass of water vapor in a given volume of moist air to the mass of water vapor in the same volume of saturated air at the same temperature and pressure
40. The coefficient of performance of Heat Pump is always __________ one.
A. equal to
B. less than
C. greater than