Heat Transfer The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation. Remains constant Decreases May increase or decrease ; depends on the material Increases Remains constant Decreases May increase or decrease ; depends on the material Increases 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 555 55.5 0.15 0.55 555 55.5 0.15 0.55 ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Kirchoff's law is applicable to Both A and B Total radiation only Monochromatic radiation only Only volumes and not to surfaces Both A and B Total radiation only Monochromatic radiation only Only volumes and not to surfaces ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Forced circulation evaporators are normally used for concentrating liquids having Scaling characteristics Both A & B High viscosity Neither A nor B Scaling characteristics Both A & B High viscosity Neither A nor B ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Analogy between mass and heat transfer is not applicable in case of Both B and C Thermal or pressure mass diffusion Same velocity profile or equal eddy diffusivities Viscous heating or chemical reaction Both B and C Thermal or pressure mass diffusion Same velocity profile or equal eddy diffusivities Viscous heating or chemical reaction ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer If Prandtl number is greater than the Schmidt number, then the none of the listed here thermal boundary layer lies inside the concentration boundary layer concentration boundary layer lies inside the thermal boundary layer thermal & concentration boundary layers are of equal thickness none of the listed here thermal boundary layer lies inside the concentration boundary layer concentration boundary layer lies inside the thermal boundary layer thermal & concentration boundary layers are of equal thickness ANSWER DOWNLOAD EXAMIANS APP
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