Heat Transfer What is the absorptivity of a black body? 0.78 1 0.95 0.78 1 0.95 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. 40 minutes 20 minutes 10 minutes 5 minutes 40 minutes 20 minutes 10 minutes 5 minutes ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The ratio of total radiating power to the absorptivity of the body depends upon the __________ as per Kirchoffs law. Nature of the body Wavelength of radiation Temperature of the body None of these Nature of the body Wavelength of radiation Temperature of the body None of these ANSWER DOWNLOAD EXAMIANS APP
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 Which area is used in case of heat flow by conduction through a cylinder ? Geometric mean area Logarithmic mean area Arithmetic mean area None of the listed here Geometric mean area Logarithmic mean area Arithmetic mean area None of the listed here ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of Concentrations Mass transfer co-efficients Activity co-efficients Chemical potentials Concentrations Mass transfer co-efficients Activity co-efficients Chemical potentials ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS