Heat and Mass Transfer Total emissivity of polished silver compared to black body is Higher Very much lower Same More or less same Higher Very much lower Same More or less same 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 = kρ/S h = ρS/k h = k/ ρS h = S/ρk h = kρ/S h = ρS/k ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer 40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is 0.45 0.4 0.55 0.75 0.45 0.4 0.55 0.75 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Kirchhoff's law states that The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature None of these The wave length corresponding to the maximum energy is proportional to the absolute temperature The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature None of these The wave length corresponding to the maximum energy is proportional to the absolute temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction is valid for Three dimensional cases only Two dimensional cases only Regular surfaces having non-uniform temperature gradients One dimensional cases only Three dimensional cases only Two dimensional cases only Regular surfaces having non-uniform temperature gradients One dimensional cases only 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) k. (dx/dT) k. (dx/dT) (dT/dx) k. (dT/dx) k. k. (dx/dT) k. (dx/dT) (dT/dx) k. (dT/dx) k. ANSWER DOWNLOAD EXAMIANS APP
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