Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. Absorptivity of a perfect black body is unity. Which of the following has maximumabsorptivity?
a. Aluminium foil
b. Refractory bricks
c. Iron plate
d. Coke breeze
Q. With the increase of temperature, the Col-burn jH factor
a. Increases
b. Decreases
c. Remains unchanged
d. May increase or decrease; depending on temperature
Q. Crystallisation of solids from a homogeneous solution is a/an __________ process.
a. Exothermic
b. Mildly endothermic
c. Highly endothermic
d. None of these
Q. Pick out the wrong statement.
a. Heat transfer by radiation cannot occur across an absolute volume
b. In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles
c. Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light
d. The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same
Q. Steam condensate is recovered by steam traps and recycled for use as boiler feed water, because of its low
a. Hardness
b. Dissolved solids content
c. Suspended solids content
d. All (A), (B) and (C)
Q. In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate.
a. Increases
b. Decreases
c. Does not affect
d. May increase or decrease, depends on the type of baffle
Q. The advantage of backward feed multiple effect evaporators over forward feed units is that
a. Heat sensitive material can be handled
b. There is no additional cost of pumping
c. Most concentrated liquid is at highest temperature
d. Equal heat transfer co-efficients exist in various effects
Q. Baffles are provided in heat exchangers to increase the
a. Fouling factor
b. Heat transfer area
c. Heat transfer co-efficient
d. Heat transfer rate
Q. Film boiling is usually not desired in commercial equipments, because
a. The heat transfer rate is low in view of the large temperature drop
b. It is difficult to maintain
c. It is not economic
d. None of these
Q. Pick out the wrong statement.
a. Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient
b. In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles
c. S.I. unit of fouling factor is Watt/m2 .°K
d. Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube
Q. A dephlegmator is a
a. Total condenser
b. Vacuum evaporator
c. Partial condenser
d. Double pipe heat exchanger
Q. Reynold's analogy states that (where, St = Stanton number f = friction factor)
a. St = f/2
b. St = f/4
c. St = 4f
d. St = f1/2
Q. Heat transfer by natural convection is enhanced in system with
a. High viscosity
b. High co-efficient of thermal expansion
c. Low temperature gradients
d. Low density change with temperature