Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. 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)
Q. Unsteady state heat conduction occurs, when
a. Temperature distribution is independent of time
b. Temperature distribution is dependent on time
c. Heat flows in one direction only
d. Three dimensional heat flow is concerned
Q. A __________ surface has the maximum thermal emissivity out of the following.
a. Black & smooth
b. Black & rough
c. White & smooth
d. White & rough
Q. For specified tube outside diameter, higher BWG means higher
a. Tube thickness
b. Cross-sectional area
c. Weight per unit length
d. None of these
Q. A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time
a. t = 283 s
b. t = 356 s
c. t = 400 s
d. t = 800 s
Q. Multiple effect evaporation is generally recommended, when the
a. Large scale evaporation of liquor is needed
b. Corrosive liquids are to be concentrated
c. Fuel is cheaply available
d. Evaporation on small scale is to be done
Q. Which of the following is correct?
a. Rate = Driving force × Resistance
b. Driving force = Rate × Resistance
c. Resistance = Driving force × Rate
d. Rate = Resistance/Driving force
Q. For a fluid flowing in an annulus space, the wetted perimeter for heat transfer andpressure drop are
a. Same
b. Different
c. Never different
d. Linearly related
Q. Steam is routed through the tube in case of a __________ evaporator.
a. Basket type
b. Horizontal tube
c. Short tube vertical
d. Long tube vertical
Q. Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the
a. Higher condensing film co-efficient is desired
b. Condensate is corrosive in nature
c. Lower pressure drop through the exchanger is desired
d. Temperature of the incoming vapor is very high
Q. Viscosity of gases __________ with increase in temperature.
a. Increase very rapidly
b. Increase slowly
c. Decrease slowly
d. Remain unaffected
Q. A cube, sphere & a thin circular plate (all having same mass and made of same material)are all heated to 300°C and allowed to cool in natural air. Which one will cool the slowest?
a. Cube
b. Plate
c. Sphere
d. All will cool at the same rate