Heat and Mass Transfer A grey body is one whose absorptivity Varies with wavelength of the incident ray Is equal to its emissivity Varies with temperature Does not vary with temperature and. wavelength of the incident ray Varies with wavelength of the incident ray Is equal to its emissivity Varies with temperature Does not vary with temperature and. wavelength of the incident ray ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Kirchhoff's law states that The wave length corresponding to the maximum energy is proportional to 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 The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature None of these The wave length corresponding to the maximum energy is proportional to 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 The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Total heat is the heat required to Change liquid into vapour Change vapour into liquid Increase the temperature of a liquid or vapour Convert water into steam and superheat it Change liquid into vapour Change vapour into liquid Increase the temperature of a liquid or vapour Convert water into steam and superheat it ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction gives the heat flow for Nonuniform temperature surfaces Two dimensional cases only Irregular surfaces One dimensional cases only Nonuniform temperature surfaces Two dimensional cases only Irregular surfaces One dimensional cases only ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is a All of these Physical property of a substance Dimensionless parameter Function of temperature All of these Physical property of a substance Dimensionless parameter Function of temperature ANSWER DOWNLOAD EXAMIANS APP
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