Heat and Mass Transfer If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called Emissivity None of these Absorptive power Emissive power Emissivity None of these Absorptive power Emissive power ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Sensible heat is the heat required to Change vapour into liquid Change liquid into vapour Increase the temperature of a liquid of vapour Convert water into steam and superheat it Change vapour into liquid Change liquid into vapour Increase the temperature of a liquid of vapour Convert water into steam and superheat it ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following would lead to a reduction in thermal resistance? In radiation, increasing the temperature and reducing the emissivity. In convection, stirring of the fluid and cleaning the heating surface. All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In radiation, increasing the temperature and reducing the emissivity. In convection, stirring of the fluid and cleaning the heating surface. All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The amount of heat flow through a body by conduction is All of these Directly proportional to the temperature difference on the two faces of the body Directly proportional to the surface area of the body Dependent upon the material of the body All of these Directly proportional to the temperature difference on the two faces of the body Directly proportional to the surface area of the body Dependent upon the material of the body 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 Two One Four Three Two One Four Three 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 63.2% of the value of initial temperature difference The time taken to attain the final temperature to be measured The time taken to attain 50% of the value of initial temperature difference Determined by the time taken to reach 100°C from 0°C 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 The time taken to attain 50% of the value of initial temperature difference ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS