Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. The rate of emission of radiation by a body does not depend upon the
a. Wavelength of radiation
b. Surface temperature of the body
c. Nature of the surface
d. Shape and porosity of the body
Q. Heat sensitive materials can be concentrated in an evaporator employing
a. Vacuum
b. High pressure
c. High residence time
d. None of these
Q. In a cooling tower, water becomes cool by
a. Loosing sensible heat
b. Heat transfer to surroundings
c. Vaporisation due to heat loss to air
d. Loosing latent heat
Q. Conductance is given by (where, x = thickness, A = heat flow area, K = thermalconductivity.)
a. x/KA
b. KA/x
c. K/Ax
d. A/Kx
Q. LMTD can't be used as such without a correction factor for the
a. Multipass heat exchanger
b. Baffled heat exchanger
c. Condensation of mixed vapour in a condenser
d. All (A) (B) and (C)
Q. What is the logarithmic mean of r1 and r2?
a. (r1 - r2)/ln(r1/r2)
b. (r1 - r2)/ln(r2/r1)
c. (r2 - r1)/ln(r1/r2)
d. (r1 - r2)/-ln(r1/r2)
Q. In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining the same, the temperature of the exit liquid will be
a. Less than 45°C
b. More than 45°C
c. Equal to 45°C
d. Initially decreases and remains constant thereafter
Q. The Nusselt number for fully developed (both thermally and hydrodynamically) laminarflow through a circular pipe, where the wall heat flux is constant, is
a. 2.36
b. 4.36
c. 120.36
d. Dependent on NRe only
Q. Heat flux, as defined in heat flow is analogous to __________ in electricity flow.
a. Current
b. Voltage
c. Resistance
d. None of these
Q. The overall resistance for heat transfer through a series of flat resistance, is the __________of the resistances.
a. Average
b. Geometric mean
c. Product
d. Sum
Q. The driving potential for the crystal growth during crystallisation is the __________ of thesolution.
a. Concentration
b. Viscosity
c. Super-saturation
d. Density
Q. Heat transfer co-efficient equation for forced convection, Nu = 0.023 Re 0.8. Prn, is not valid, if the value of
a. n = 0.4 is used for heating
b. n = 0.3 is used for cooling
c. Reynolds number for the flow involved is > 10000
d. Reynolds number for the flow involved is < 2100
Q. In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger.
a. Once
b. Twice
c. Thrice
d. Four times