210) The refrigerant widely used in domestic refrigerators is

211) When absorptivity (?) = 1, reflectivity (?) = 0 and transmittivity (?) = 0, then the body is said to be a

212) Prandtl number (P_N) is given by P_N = ?.c_p/k.

213) In a vapour compression system, the condition of refrigerant before passing through the condenser is

214) A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be