Heat and Mass Transfer Which of the following would lead to a reduction in thermal resistance? All of these In convection, stirring of the fluid and cleaning the heating surface. In radiation, increasing the temperature and reducing the emissivity. In conduction, reduction in the thickness of the material and an increase in thermal conductivity. All of these In convection, stirring of the fluid and cleaning the heating surface. In radiation, increasing the temperature and reducing the emissivity. In conduction, reduction in the thickness of the material and an increase in thermal conductivity. ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer by conduction through a thick sphere is given by Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When heat is transferred from hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by Conduction and convection Conduction Convection Radiation Conduction and convection Conduction Convection Radiation ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The time constant of a thermocouple is The time taken to attain 50% of the value of initial temperature difference The time taken to attain the final temperature to be measured The time taken to attain 63.2% of the value of initial temperature difference 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 the final temperature to be measured The time taken to attain 63.2% of the value of initial temperature difference Determined by the time taken to reach 100°C from 0°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A steam pipe is to be insulated by two insulating materials put over each other. For best results Whether to put inferior OIL over pipe or the better one would depend on steam temperature Better insulation should be put over pipe and better one over it Both may be put in any order Inferior insulation should be put over pipe and better one over it Whether to put inferior OIL over pipe or the better one would depend on steam temperature Better insulation should be put over pipe and better one over it Both may be put in any order Inferior insulation should be put over pipe and better one over it ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called Stefan's law First law of thermodynamics Newton's law of cooling Newton's law of heating Stefan's law First law of thermodynamics Newton's law of cooling Newton's law of heating ANSWER DOWNLOAD EXAMIANS APP
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