Heat and Mass Transfer If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of 3 9 81 270 3 9 81 270 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the energy absorbed by the body to total energy falling on it is called Absorptivity Emissivity Emissive power Absorptive power Absorptivity Emissivity Emissive power Absorptive power ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following is the case of heat transfer by radiation? Cooling of parts in furnace Heat received by a person from fireplace Blast furnace Heating of building Cooling of parts in furnace Heat received by a person from fireplace Blast furnace Heating of building ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The thermal diffusivities for solids are generally More or less same as for liquids and gases Less than those for liquids Less than those for gases More than those for liquids and gases More or less same as for liquids and gases Less than those for liquids Less than those for gases More than those for liquids and gases ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Kirchhoff's law states that The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body None of these The wave length corresponding to the maximum energy is proportional to the absolute temperature The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body None of these The wave length corresponding to the maximum energy is proportional to the absolute temperature The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body) k. (dT/dx) (dx/dT) k. k. (dT/dx) k. (dx/dT) k. (dT/dx) (dx/dT) k. k. (dT/dx) k. (dx/dT) ANSWER DOWNLOAD EXAMIANS APP
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