What is the absorptivity of a black body?
What is the absorptivity of a black body?
A. 1
B. 0
C. 0.78
D. 0.95
Similar Posts
Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because___________________?
Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because___________________?A. Convection becomes important
B. Conduction becomes important
C. Radiation becomes important
D. Sub-cooled boiling occursRadiator of an automobile engine is a ______________ type of heat exchanger?
Radiator of an automobile engine is a ______________ type of heat exchanger?A. Co-current
B. Cross-current
C. Counter-current
D. Direct contactThe energy radiated from a surface Q at absolute temperature T is related as__________________?
The energy radiated from a surface Q at absolute temperature T is related as__________________?A. Q ∝ T2
B. Q ∝ T4
C. Q ∝ T3
D. None of theseA multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?
A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?A. Lower heat transfer area
B. Lower steam economy
C. Higher steam economy
D. Higher solute concentration in the productA hollow sphere and a solid sphere of the same material and equal radii are heated to the same temperature. In this case ?
A hollow sphere and a solid sphere of the same material and equal radii are heated to the same temperature. In this case ?A. The cooling rate will be the same for the two spheres and hence the two spheres will have
equal temperatures at any instant
B. Both the spheres will emit equal amount of radiation per unit time in the beginning
C. Both will absorb equal amount of radiation from the surrounding in the beginning
D. Both B. & C.For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area___________________?
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area___________________?A. Increases
B. Decreases
C. Remain constant
D. Passes through a maxima