51. A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be
52. The curved lines on a psychrometric chart indicates
53. During humidification process, __________ increases.
54. A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
55. The counter-current flow heat exchanger can transfer __________ heat than parallel flow heat exchanger.
56. The freon group of refrigerants are
57. For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is __________ that for counter flow.
58. A vapour absorption refrigerator uses __________ as a refrigerant.
59. Thermal conductivity of air increases with rise in temperature.
60. The material of pipe lines for a system using ammonia as a refrigerant should be copper.
61. The wave length corresponding to the maximum energy is inversely proportional to the absolute temperature. This statement is called Planck's law.
62. Which of the following refrigerant has the highest freezing point.
63. Air conditioning means
64. The emissivity for a black body is
65. Which of the following would lead to a reduction in thermal resistance?
66. 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
67. Free convection flow depends on
68. The critical pressure of a liquid is the pressure
69. Conduction is a process of heat transfer
70. Thermal diffusivity of a substance is
71. Chemical name of chalk is?
72. Fouling factor is used
73. The natural convection air cooled condensers are used in
74. The process, generally used in winter air-conditioning to warm and humidity the air, is called
75. At 100% relative humidity, wet bulb temperature, dry bulb temperature, dew point temperature and saturation temperature are equal.