Heat and Mass Transfer The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to -1 =-1/3 1 =-2/3 -1 =-1/3 1 =-2/3 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. k. (dT/dx) k. k. (dx/dT) (dx/dT) (dT/dx) k. k. (dT/dx) k. k. (dx/dT) (dx/dT) (dT/dx) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m²). The critical thickness of insulation will be 40 mm 800 mm 160 mm 25 mm 40 mm 800 mm 160 mm 25 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When α is absorptivity, ρ is reflectivity and τ is transmissivity, then for a diathermanous body, α + ρ = 1 and τ = 0 α = 1, ρ = 0 and τ = 0 α = 0, ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 α + ρ = 1 and τ = 0 α = 1, ρ = 0 and τ = 0 α = 0, ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is 60°C 20°C 66.7°C 40°C 60°C 20°C 66.7°C 40°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Planck’s law holds good for All of these black bodies all coloured bodies polished bodies All of these black bodies all coloured bodies polished bodies ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS