Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer

From 781 to 795 of 836

Q. Forced circulation evaporators are normally used for concentrating liquids having

a. Scaling characteristics

b. High viscosity

c. Both (A) & (B)

d. Neither (A) nor (B)

  • c. Both (A) & (B)

Q. Radiation energy is emitted by all the substances, which are above

a. 0°K

b. 0°C

c. 100°C

d. Room temperature

  • a. 0°K

Q. View factor is important in heat transfer by

a. Steady state conduction

b. Natural convection

c. Forced convection

d. Radiation

  • d. Radiation

Q. Pick out the wrong statement.

a. Economy of a multiple effect evaporator is not influenced by the boiling point elevation

b. Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature

c. Double pipe heat exchangers are mostly used in the field of refrigeration

d. Finned tube heat exchangers are suitable for heating air by steam

  • b. Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature

Q. 'Duhring's plot' is of use in

a. Extractive distillation

b. Evaporation

c. Leaching

d. Absorption

  • b. Evaporation

Q. The dimensionless group in mass transfer that is equivalent to Prandtl number in heattransfer is

a. Nusselt number

b. Sherwood number

c. Schmidt number

d. Stanton number

  • c. Schmidt number

Q. Pick out the wrong statement.

a. In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2

b. Sherwood number in mass transfer corresponds to Nusselt number in heat transfer and Schmidt number to Prandtl number

c. Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger

d. Hot gases at moderate pressure are usually in the shell side of shell and tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side

  • c. Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger

Q. Loss of heat from untagged steam pipe to the ambient air is by

a. Conduction

b. Convection

c. Radiation

d. All (A), (B) & (C)

  • d. All (A), (B) & (C)

Q. In Biot number, the characteristic length used is the ratio of the __________ of the solid.

a. Volume to surface area

b. Perimeter to surface area

c. Surface area to volume

d. Surface area to perimeter

  • a. Volume to surface area

Q. Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heatflux vs. temperature drop for a boiling liquid, because

a. Convection becomes important

b. Conduction becomes important

c. Radiation becomes important

d. Sub-cooled boiling occurs

  • c. Radiation becomes important

Q. Which has the lowest Prandtl number?

a. Liquid metal

b. Aqueous solution

c. Water

d. Lube oil

  • a. Liquid metal
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