Which has the lowest Prandtl number ?
Which has the lowest Prandtl number ?
A. Liquid metal
B. Aqueous solution
C. Water
D. Lube oil
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Heat transfer by radiation between two bodies at T1 & T2 and in an ambient temperature of Ta°C depends on_____________?
Heat transfer by radiation between two bodies at T1 & T2 and in an ambient temperature of Ta°C depends on_____________?A. T1 – T2
B. T1 – Ta
C. T2 – Ta
D. None of theseA measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the _______________ number?
A measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the _______________ number?A. Condensation
B. Grashoff
C. Stanton
D. BrinkmanForced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?
Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?A. Long vertical evaporator
B. Horizontal tube evaporator
C. Agitated film evaporator
D. Calandria vertical tube evaporatorThe heat flux in the nucleate boiling regimes is proportional to (where, ΔT = excess temperature) ?
The heat flux in the nucleate boiling regimes is proportional to (where, ΔT = excess temperature) ?A. (ΔT)2
B. (ΔT)4
C. (ΔT)3
D. √(ΔT)A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?
A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?A. t = 283 s
B. t = 356 s
C. t = 400 s
D. t = 800 sFor a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would ?
For a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would ?A. Decrease
B. Increase
C. First decrease and then increase
D. First increase and then decrease