17) The wet bulb temperature lines, on the psychrometric chart, are curved lines.

18) Thermal diffusivity is a

19) The condition of refrigerant after leaving the compressor and before entering the condenser is superheated vapour.

20) The total radiation from a black body per second per unit area is __________ fourth power of the absolute temperature. This statement is known as Stefan-Boltzmann law.

21) In a psychrometric process, the sensible heat added is 30 kJ/s and the latent heat added is 20 kJ/s. The sensible heat factor for the process will be