Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. The maximum heat transfer co-efficient from steam heating will be attained when thesteam is:
a. Supersaturated
b. Saturated
c. Wet
d. None of these
Q. One kilogram of water at 0°C is changed to superheated steam of one atm pressure and300° C. The major heat consumption in the process will be to
a. Heat the water from 0°C to 100°C
b. Evaporate the water
c. To superheat the steam
d. Data insufficient, can't be predicted
Q. The film co-efficient is decreased due to the presence of non-condensing gases in the vapors.The film co-efficient of superheated vapor as compared to that of saturated vapor is
a. More
b. Less
c. Some
d. Either more or less; depends on the nature of vapor
Q. The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipein laminar flow are
a. Re.Gz
b. Nu, Pr
c. Nu, Pr, Re
d. Nu, Gz
Q. In case of heat transfer by conduction in a hollow cylinder, __________ mean area is usedto calculate the heat transfer rate.
a. Geometric
b. Arithmetic
c. Logarithmic
d. Either (A), (B) or (C)
Q. The absorptivity of a grey body at a given temperature __________ with increasingwavelength of radiation.
a. Increases
b. Decreases
c. Remain constant
d. May increase or decrease; depends on the material
Q. Forced circulation evaporators are useful for the concentration of viscous, salting and scaleforming 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 evaporator
Q. Nusselt number is the ratio of the temperature gradient at the wall to
a. Temperature difference
b. Heat flux
c. That across the entire pipe
d. None of these
Q. Which of the following has the lowest overall heat transfer co-efficient?
a. Dowtherm
b. Molten sodium
c. Water
d. Air
Q. What is the unit of thermal conductivity?
a. Kcal/hr. m2°C
b. Kcal/hr.m.°C
c. Kcal/hr.m
d. Kcal/hr. °C
Q. Indirect contact heat exchangers are preferred over direct contact heat exchangers,because
a. Heat transfer co-efficient are high
b. There is no risk of contamination
c. There is no mist formation
d. Cost of equipment is lower
Q. Tubes are held between top and bottom tube sheets in Calandria type evaporator by keeping
a. Both the tube sheets fixed
b. Both the tube sheets floating
c. The top tube sheet floating and bottom tube sheet fixed
d. The top tube sheet fixed and the bottom tube-sheet floating