Heat and Mass Transfer The use of heat exchangers is made in Condensers and boilers in steam plants Radiators in automobile Condensers and evaporators in refrigeration and air conditioning units All of these Condensers and boilers in steam plants Radiators in automobile Condensers and evaporators in refrigeration and air conditioning units All of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number is the ratio of Energy transferred by convection to that by conduction Kinematic viscosity to thermal diffusivity Inertia force to viscous force None of these Energy transferred by convection to that by conduction Kinematic viscosity to thermal diffusivity Inertia force to viscous force None of these 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. (dT/dx) k. A. (dx/dT) k. A. (dT/dx) k. (dx/dT) k. (dT/dx) k. A. (dx/dT) k. A. (dT/dx) k. (dx/dT) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of solid metals with rise in temperature normally Remain constant Decreases May increase or decrease depending on temperature Increases Remain constant Decreases May increase or decrease depending on temperature Increases 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/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Free convection flow depends on Coefficient of viscosity Gravitational force Density All of these Coefficient of viscosity Gravitational force Density All of these ANSWER DOWNLOAD EXAMIANS APP
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