Heat and Mass Transfer Moisture would find its way into insulation by vapour pressure unless it is prevented by High vapour pressure High thickness of insulation Less thermal conductivity insulator A vapour seal High vapour pressure High thickness of insulation Less thermal conductivity insulator A vapour seal ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h₁, h₂ and h₃ respectively. The average heat transfer coefficient for the cube is 1/h₁ + 1/h₂ + 1/h₃ None of these (h₁.h₂.h₃)1/3 h₁ + h₂ + h₃ 1/h₁ + 1/h₂ + 1/h₃ None of these (h₁.h₂.h₃)1/3 h₁ + h₂ + h₃ ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According of Kirchhoff's law Radiant heat is proportional to fourth power of absolute temperature Emissive power depends on temperature Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body Emissive power and absorptivity are constant for all bodies Radiant heat is proportional to fourth power of absolute temperature Emissive power depends on temperature Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body Emissive power and absorptivity are constant for all bodies ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of the wavelength for maximum emissive power is given by Fourier's law Wien’s law Stefan's law Planck's law Fourier's law Wien’s law Stefan's law Planck's law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan's law, the total radiation from a black body per second per unit area is proportional to T T5 T2 Absolute temperature T T5 T2 Absolute temperature 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 Three One Two Four Three One Two Four ANSWER DOWNLOAD EXAMIANS APP
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