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 =-1/3 =-2/3 -1 1 =-1/3 =-2/3 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In heat transfer, conductance equals conductivity (kcal/hr/sq.m/°C/cm) divided by Hr (time) Sq. m (area) °C (temperature) K.cal (heat) Hr (time) Sq. m (area) °C (temperature) K.cal (heat) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of solid metals with rise in temperature normally May increase or decrease depending on temperature Increases Remain constant Decreases May increase or decrease depending on temperature Increases Remain constant Decreases ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Sensible heat is the heat required to Increase the temperature of a liquid of vapour Convert water into steam and superheat it Change liquid into vapour Change vapour into liquid Increase the temperature of a liquid of vapour Convert water into steam and superheat it Change liquid into vapour Change vapour into liquid ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of the wavelength for maximum emissive power is given by Planck's law Wien’s law Stefan's law Fourier's law Planck's law Wien’s law Stefan's law Fourier's law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity of a substance is All of these Directly proportional to the thermal conductivity Inversely proportional to density of substance Inversely proportional to specific heat All of these Directly proportional to the thermal conductivity Inversely proportional to density of substance Inversely proportional to specific heat ANSWER DOWNLOAD EXAMIANS APP