Heat and Mass Transfer Which of the following would lead to a reduction in thermal resistance? In convection, stirring of the fluid and cleaning the heating surface. In conduction, reduction in the thickness of the material and an increase in thermal conductivity. All of these In radiation, increasing the temperature and reducing the emissivity. In convection, stirring of the fluid and cleaning the heating surface. In conduction, reduction in the thickness of the material and an increase in thermal conductivity. All of these In radiation, increasing the temperature and reducing the emissivity. ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly have radiation heat exchange between them. It is desired to reduce 75% of the radiant heat transfer by inserting thin parallel shields of emissivity 1 on both sides. The number of shields should be Four One Three Two Four One Three Two ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water in general with rise in temperature Remain constant Decreases May increase or decrease depending on temperature Increases Remain constant Decreases May increase or decrease depending on temperature Increases ANSWER DOWNLOAD EXAMIANS APP
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 40 mm 160 mm 25 mm 800 mm 40 mm 160 mm 25 mm 800 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number is the ratio of Inertia force to viscous force None of these Kinematic viscosity to thermal diffusivity Energy transferred by convection to that by conduction Inertia force to viscous force None of these Kinematic viscosity to thermal diffusivity Energy transferred by convection to that by conduction ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Heat transfer by radiation mainly depends upon Nature of the body Its temperature Kind and extent of its surface All of these Nature of the body Its temperature Kind and extent of its surface All of these ANSWER DOWNLOAD EXAMIANS APP
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