Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it
a. Decreases the pressure drop
b. Decreases the outlet temperature of cooling medium
c. Increases the overall heat transfer coefficient
d. None of these
Q. A tank painted with which of the following coloured paints, would heat up maximum by radiation from sun?
a. Yellow paint
b. White paint
c. Black paint
d. Grey paint
Q. Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade?
a. 35.5
b. 43.75
c. 81.25
d. 48.25
Q. A graph between __________ is called Wilson plot.
a. (1/U) Vs. (1/v 0.8)
b. (1/v 0.8) Vs. U
c. v 0.8 Vs . U
d. (1/U) Vs. (1/V)
Q. The thermal radiation emitted by a body is proportional to T n, where T is its absolute temperature. The value of 'n' is exactly 4 for
a. Black painted bodies only
b. All bodies
c. Polished bodies only
d. A black body
Q. Pick out the correct statement.
a. 1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F
b. In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity
c. In unsteady state heat conduction, heat flows in the direction of temperature rise
d. In heat transfer by forced convection, Grashoff number is very important
Q. Evaporation by thermo compression results in the
a. Saving of steam
b. Realisation of multiple effect economy in a single effect
c. Both (A) and (B)
d. None of these
Q. Fouling factor for a heat exchanger is given by (where, U1 = heat transfer co-efficient ofdirty surface U2 = heat transfer co-efficient of clean surface).
a. U1 - U2
b. 1/U1 - 1/U2
c. 1/U2 - 1/U1
d. U2 - U1
Q. Use of transverse baffles in a shell and tube heat exchanger is done to increase the
a. Rate of heat transfer
b. Flow velocity
c. Turbulence of shell side fluid
d. All (A), (B) and (C)
Q. All analogy equations connecting friction factor and heat transfer co-efficient apply only to
a. Wall or skin friction
b. Form friction
c. Both (A) and (B)
d. Turbulent flow
Q. Which of the following situations can be approximated to a steady state heat transfer system?
a. A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at 35°C
b. 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C
c. Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C
d. A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C
Q. Reason for operating an evaporator in multiple effects is to secure
a. Increased steam economy
b. Decreased steam consumption
c. Both (A) and (B)
d. Increased capacity
Q. Heat transfer by __________ may not necessarily require the presence of a medium.
a. Conduction
b. Natural convection
c. Forced convection
d. Radiation