Heat and Mass Transfer An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m²). The critical thickness of insulation will be 25 mm 160 mm 800 mm 40 mm 25 mm 160 mm 800 mm 40 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The concept of overall coefficient of heat transfer is used in heat transfer problems of Radiation Conduction Conduction and convection Convection Radiation Conduction Conduction and convection Convection ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be black when (Where a = absorptivity, p = reflectivity, X = transmissivity.) P = 0, x = 1 and a = 0 X = 0, a + p = 0 P = 0, x = 0 and a = 1 P= 1, T = 0 and a = 0 P = 0, x = 1 and a = 0 X = 0, a + p = 0 P = 0, x = 0 and a = 1 P= 1, T = 0 and a = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity of a substance is given by (where h = Thermal diffusivity, ρ = Density of substance, S = Specific heat, and k = Thermal conductivity) h = k/ ρS h = S/ρk h = ρS/k h = kρ/S h = k/ ρS h = S/ρk h = ρS/k h = kρ/S ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer 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 =-2/3 =-1/3 -1 1 =-2/3 =-1/3 -1 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A perfect black body is one which Transmits all heat radiations Reflects all heat Absorbs heat radiations of all wave lengths falling on it Is black in colour Transmits all heat radiations Reflects all heat Absorbs heat radiations of all wave lengths falling on it Is black in colour ANSWER DOWNLOAD EXAMIANS APP
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