Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. The actual temperature drop across the heating surface of an evaporator depends on the
a. Liquid depth over the heating surface
b. Solution being evaporated
c. Pressure difference between the steam chest and the vapor space above the boiling liquid
d. All (A), (B) and (C)
Q. In SI units, thermal conductivity is expressed in
a. Watt/m.°K
b. Watt/m2. °K
c. Watt/m2. °K
d. Watt/m4. °K
Q. jH factor for heat transfer depends upon the __________ number.
a. Biot
b. Nusselt
c. Reynolds
d. Prandtl
Q. In pipe flow, heat is transferred from hot wall to the liquid by
a. Conduction only
b. Forced convection only
c. Forced convection and conduction
d. Free and forced convection
Q. A perfect black body is a perfect __________ of radiation.
a. Absorber
b. Emitter
c. Both (A) & (B)
d. Neither (A) nor (B)
Q. Heat transfer rate described by Fourier's law will decrease, if the __________ increases.
a. Thermal conductivity
b. Thickness
c. Temperature difference
d. Heat transfer area
Q. The absorptivity of a body is equal to its emissivity
a. At a particular temperature
b. For circular bodies
c. Under thermal equilibrium
d. None of these
Q. In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will
a. Increase
b. Decrease
c. Remain unchanged
d. Either increase or decrease; depends on the coolant flow rate
Q. Which one gives the monochromatic emissive power for black body radiation?
a. Planck's law
b. Kirchhoff’s law
c. Wien's law
d. Stefan-Boltzmann law
Q. If heat transfer rate varies with the time, it is termed as
a. Forced convection
b. Steady state conduction
c. Monochromatic radiation
d. None of these
Q. __________ heat exchanger is used for chilling oil to be dewaxed.
a. U-tube
b. Double pipe
c. Fixed tube
d. Floating head
Q. Pick out the correct equation.
a. jH = (St)(Pr) 2/3 = f/2
b. jH = (St)(Pr) 1/3 = f/2
c. jH = (St) 2/3(Pr) = f/2
d. jH = (St) 1/3(Pr) = f/2
Q. It is not preferable to use superheated steam in evaporators, because of its very
a. High temperature
b. High pressure
c. Low film co-efficient
d. None of these