Heat and Mass Transfer The thermal diffusivities for gases are generally Less than those for liquids More than those for solids More than those for liquids Dependent on the viscosity Less than those for liquids More than those for solids More than those for liquids Dependent on the viscosity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The time constant of a thermocouple is Determined by the time taken to reach 100°C from 0°C The time taken to attain 50% of the value of initial temperature difference The time taken to attain 63.2% of the value of initial temperature difference The time taken to attain the final temperature to be measured Determined by the time taken to reach 100°C from 0°C The time taken to attain 50% of the value of initial temperature difference The time taken to attain 63.2% of the value of initial temperature difference The time taken to attain the final temperature to be measured ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the Reynold's number, Grashoff's number Prandtl number, Grashoff's number Grashoff's number Reynold's number Reynold's number, Grashoff's number Prandtl number, Grashoff's number Grashoff's number Reynold's number 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. A. (dT/dx) k. A. (dx/dT) k. (dx/dT) k. (dT/dx) k. A. (dT/dx) k. A. (dx/dT) k. (dx/dT) k. (dT/dx) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer, The better insulation must be put outside One should take into account the steam temperature before deciding as to which insulation is put where The better insulation must be put inside One could place either insulation on either side The better insulation must be put outside One should take into account the steam temperature before deciding as to which insulation is put where The better insulation must be put inside One could place either insulation on either side 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
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