Heat Transfer In the equation Q = UAΔt; Δt is Geometric mean temperature difference The difference of average bulk temperatures of hot and cold fluids Arithmetic mean temperature difference Logarithmic mean temperature difference Geometric mean temperature difference The difference of average bulk temperatures of hot and cold fluids Arithmetic mean temperature difference Logarithmic mean temperature difference ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient Increases Decreases Is not affected May increase or decrease; depends on the feed Increases Decreases Is not affected May increase or decrease; depends on the feed ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Heat transfer occurs by natural convection because change in temperature causes difference in Thermal conductivity Density Viscosity Heat capacity Thermal conductivity Density Viscosity Heat capacity ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness) ∝ t ∝ 1/t ∝ √t Independent of 't' ∝ t ∝ 1/t ∝ √t Independent of 't' ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium. This is __________ law. Stefan-Boltzman Planck's Wien's displacement Kirchoffs Stefan-Boltzman Planck's Wien's displacement Kirchoffs ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer A metal ball of radius 0.1 m at a uniform temperature of 90°C is left in air at 30°C. The density and the specific heat of the metal are 3000 kg/m³ and 0.4 kJ/kg.K respectively. The heat transfer co-efficient is 50 W/m².K Neglecting the temperature gradients inside the ball, the time taken (in hours) for the ball to cool to 60°C is 55.5 0.15 555 0.55 55.5 0.15 555 0.55 ANSWER DOWNLOAD EXAMIANS APP
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