Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. Agitated film evaporator is suitable for concentrating __________ liquids.
a. Foaming
b. Viscous
c. Very thin
d. Corrosive
Q. Kirchoff's law is applicable to
a. Monochromatic radiation only
b. Total radiation only
c. Both (A) and (B)
d. Only volumes and not to surfaces
Q. The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2 . The flux, when the element temperature is increased to 1000°Cfor the same furnace temperature is
a. 11.2 kW/m2
b. 12.0 kW/m2
c. 14.6 kW/m2
d. 16.5 kW/m2
Q. With increase in temperature, the thermal conductivity of non-metallic amorphous solids
a. Decreases
b. Increases
c. Remain constant
d. First decreases upto certain temperature and then increases
Q. The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re) 0.8 (Pr) 0.4] cannot be used for
a. Low Reynold's number
b. Very low Grashoff number
c. Molten metals
d. All (A), (B) and (C)
Q. A black body when hot, emits heat radiation of __________ wavelengths.
a. Small
b. Large
c. All
d. One fixed
Q. Tube pitch is the __________ of tube diameters and the clearances.
a. Sum
b. Difference
c. Ratio
d. None of these
Q. Heat transfer rate per unit area is called
a. Thermal conductivity
b. Heat flux
c. Heat transfer co-efficient
d. Thermal diffusivity
Q. The unit of heat transfer co-efficient is
a. BTU/hr. ft2°F
b. BTU/hr. °F. ft
c. BTU/hr. °F
d. BTU/hr. ft
Q. The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are
a. (COP)R = (COP)HP = 0.6
b. (COP)R = 2.5; (COP)HP = 1.5
c. (COP)R = 1.5; (COP)HP = 2.5
d. (COP)R = (COP)HP = 2.5
Q. For what value of Prandtl number, the Col-burn analogy is valid?
a. 0.06 to 120
b. 0.6 to 120
c. 1 to 103
d. 1 to 50