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 160 mm 800 mm 25 mm 40 mm 160 mm 800 mm 25 mm 40 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water at 20°C is of the order of 0.23 0.42 0.51 0.1 0.23 0.42 0.51 0.1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A steam pipe is to be insulated by two insulating materials put over each other. For best results Better insulation should be put over pipe and better one over it Both may be put in any order Whether to put inferior OIL over pipe or the better one would depend on steam temperature Inferior insulation should be put over pipe and better one over it Better insulation should be put over pipe and better one over it Both may be put in any order Whether to put inferior OIL over pipe or the better one would depend on steam temperature Inferior insulation should be put over pipe and better one over it ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water in general with rise in temperature Remain constant Decreases Increases May increase or decrease depending on temperature Remain constant Decreases Increases May increase or decrease depending on temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The critical thickness of insulation for a sphere is k/h₀ 2k/h₀ h₀/k h₀/2k k/h₀ 2k/h₀ h₀/k h₀/2k ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number (RN) is given by (where h = Film coefficient, l = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, ρ = Density of fluid, cp = Specific heat at constant pressure, and μ = Coefficient of absolute viscosity) RN = V²/t.cp RN = ρ V l /μ RN = hl/k RN = μ cp/k RN = V²/t.cp RN = ρ V l /μ RN = hl/k RN = μ cp/k ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS