Heat and Mass Transfer A perfect black body is one which Is black in colour Reflects all heat Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations Is black in colour Reflects all heat Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations 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 None of these h₁ + h₂ + h₃ (h₁.h₂.h₃)1/3 1/h₁ + 1/h₂ + 1/h₃ None of these h₁ + h₂ + h₃ (h₁.h₂.h₃)1/3 1/h₁ + 1/h₂ + 1/h₃ ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of the wave length for maximum emissive power is given by Wine’s law Stefan’s law Planck’s law Kirchhoff’s law Wine’s law Stefan’s law Planck’s law Kirchhoff’s law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The unit of Stefan Boltzmann constant is watt2/cm °K⁴ watt/cm3 °K watt/cm2 °K⁴ watt/cm4 °K watt2/cm °K⁴ watt/cm3 °K watt/cm2 °K⁴ watt/cm4 °K 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 Absorptive power Emissive power Emissivity Absorptivity Absorptive power Emissive power Emissivity Absorptivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan Boltzmann law, the total radiation from a black body per second per unit area is directly proportional to the Absolute temperature Fourth power of the absolute temperature Square of the absolute temperature Cube of the absolute temperature Absolute temperature Fourth power of the absolute temperature Square of the absolute temperature Cube of the absolute temperature ANSWER DOWNLOAD EXAMIANS APP
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