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 = kρ/S h = S/ρk h = ρS/k h = k/ ρS h = kρ/S h = S/ρk h = ρS/k h = k/ ρS ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly have radiation heat exchange between them. It is desired to reduce 75% of the radiant heat transfer by inserting thin parallel shields of emissivity 1 on both sides. The number of shields should be Four Two One Three Four Two One Three ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, body will be transparent when (Where a = absorptivity, p = reflectivity, x = transmissivity) X = 0, a + p = 1 P = 0, x = 0 and a = 1 P = 0, x= 1, and a = 0 P=1, x = 0, and a = 0 X = 0, a + p = 1 P = 0, x = 0 and a = 1 P = 0, x= 1, and a = 0 P=1, x = 0, and a = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The highest thermal diffusivity is of Iron Concrete Lead Wood Iron Concrete Lead Wood ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number is the ratio of Inertia force to viscous force Energy transferred by convection to that by conduction None of these Kinematic viscosity to thermal diffusivity Inertia force to viscous force Energy transferred by convection to that by conduction None of these Kinematic viscosity to thermal diffusivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as Emissivity Intensity of radiation Reflectivity Transmissivity Emissivity Intensity of radiation Reflectivity Transmissivity ANSWER DOWNLOAD EXAMIANS APP
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