Heat and Mass Transfer Conduction is a process of heat transfer None of these From one particle of the body to another by the actual motion of the heated particles From one particle of the body to another without the actual motion of the particles From a hot body to a cold body, in a straight line, without affecting the intervening medium None of these From one particle of the body to another by the actual motion of the heated particles From one particle of the body to another without the actual motion of the particles From a hot body to a cold body, in a straight line, without affecting the intervening medium ANSWER DOWNLOAD EXAMIANS APP
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. Directly proportional to Equal to None of these Inversely proportional to Directly proportional to Equal to None of these Inversely proportional to 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) (dT/dx) (dx/dT) k. k. (dT/dx) k. k. (dx/dT) (dT/dx) (dx/dT) k. k. (dT/dx) k. k. (dx/dT) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of non-metallic amorphous solids with decrease in temperature Increases May increase or decrease depending on temperature Decreases Remain constant Increases May increase or decrease depending on temperature Decreases Remain constant 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 = kρ/S h = ρS/k h = S/ρk h = k/ ρS h = kρ/S h = ρS/k h = S/ρk h = k/ ρS ANSWER DOWNLOAD EXAMIANS APP