Heat and Mass Transfer In heat transfer, conductance equals conductivity (kcal/hr/sq.m/°C/cm) divided by Sq. m (area) °C (temperature) Hr (time) K.cal (heat) Sq. m (area) °C (temperature) Hr (time) K.cal (heat) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction is valid for One dimensional cases only Three dimensional cases only Two dimensional cases only Regular surfaces having non-uniform temperature gradients One dimensional cases only Three dimensional cases only Two dimensional cases only Regular surfaces having non-uniform temperature gradients ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number is the ratio of Energy transferred by convection to that by conduction Inertia force to viscous force Kinematic viscosity to thermal diffusivity None of these Energy transferred by convection to that by conduction Inertia force to viscous force Kinematic viscosity to thermal diffusivity None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water in general with rise in temperature May increase or decrease depending on temperature Increases Decreases Remain constant May increase or decrease depending on temperature Increases Decreases Remain constant ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer takes place according to Second law of thermodynamics First law of thermodynamics Kirchhoff's law Zeroth law of thermodynamics Second law of thermodynamics First law of thermodynamics Kirchhoff's law Zeroth law of thermodynamics ANSWER DOWNLOAD EXAMIANS APP
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