Heat and Mass Transfer 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. Equal to None of these Directly proportional to Inversely proportional to Equal to None of these Directly proportional to Inversely proportional to ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in Counter flow Cross flow All of these Parallel flow Counter flow Cross flow All of these Parallel flow ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following property of air does not increase with rise in temperature? Dynamic viscosity Thermal diffusivity Density Thermal conductivity Dynamic viscosity Thermal diffusivity Density Thermal conductivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The emissivity for a black body is 0.5 0.75 1 0.5 0.75 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer 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 2 k₁ k₂/ (k₁ + k₂) k₁ k₂ (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ 2 k₁ k₂/ (k₁ + k₂) k₁ k₂ (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body) (dx/dT) (dT/dx) k. k. (dT/dx) k. k. (dx/dT) (dx/dT) (dT/dx) k. k. (dT/dx) k. k. (dx/dT) ANSWER DOWNLOAD EXAMIANS APP
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