Heat Transfer The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation. Decreases Remains constant Increases May increase or decrease ; depends on the material Decreases Remains constant Increases May increase or decrease ; depends on the material ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Nusselt number is the ratio of the Temperature difference to the temperature gradient at the wall Temperature gradient of the wall to that across the entire pipe None of these Heat flux at the wall to that across the entire pipe Temperature difference to the temperature gradient at the wall Temperature gradient of the wall to that across the entire pipe None of these Heat flux at the wall to that across the entire pipe ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions ? Assume that the conductive heat transfer co-efficient is infinitely large. 20 minutes 5 minutes 10 minutes 40 minutes 20 minutes 5 minutes 10 minutes 40 minutes ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer A BTU/hr.ft.2 °F is equal to None of these 4.88 kcal/hr. m.2°C 1 kcal/hr. m².°K 1 kcal/hr. m²°C None of these 4.88 kcal/hr. m.2°C 1 kcal/hr. m².°K 1 kcal/hr. m²°C ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The purpose of providing a 'catchall' in the vapor line of an evaporator is to Arrest the entrained liquid Regulate the vapor flow Create vacuum Vent the non-condensible gases Arrest the entrained liquid Regulate the vapor flow Create vacuum Vent the non-condensible gases ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Which of the following situations can be approximated to a steady state heat transfer system? A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmosheric air at 35°C Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C 10 kg of dry saturated steam at 8 kgf/cm² flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmosheric air at 35°C Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C 10 kg of dry saturated steam at 8 kgf/cm² flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS