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

From 586 to 600 of 836

Q. a micron is equal to

a. 10-6 metres

b. 10-8 metres

c. 10-5 metres

d. 10-12 metres

e. 10-4 metres

  • a. 10-6 metres

Q. The process of heat transfer during the re-entry of satellites and missiles, at very high speeds, into the earth's atmosphere is known as

a. Radiation

b. Viscous dissipation

c. Triple flow

d. Ablation

e. None of the above

  • d. Ablation

Q. A slab of ice has one-half covered with black cloth and the other half with white cloth. The slab is now placed in sunlight. It will be observed that

a. 37,500 kg

b. more ice will melt under black cloth

c. more ice will melt under white cloth

d. ice will not melt

e. equal amount of ice will melt under the two cloths

  • b. more ice will melt under black cloth

Q. In which of the following will the evaporation rate be large?

a. Leaking water from pipe.

b. Near the mountain

c. Covered swimming pool

d. Narrow river surrounded by trees

e. Salt pan near the sea

  • b. Near the mountain

Q. A body which transmits all the radiations falling on it is known as

a. Black body

b. Grey body

c. Transparent body

d. White body

e. None of the above

  • c. Transparent body

Q. The value of the wavelength for maximum emissive power is given by

a. Stefan law

b. Wein's law

c. Planck's law

d. Kirchhoff's law

e. D'Alembert's rule

  • b. Wein's law

Q. The material preferred for the fabrication of fruit juice concentrator is

a. Mild steel sheet

b. Brass

c. Cast iron

d. Stainless steel sheet

e. Copper

  • d. Stainless steel sheet

Q. Gases have poor

a. Absorptivity

b. Transmissivity

c. Reflectivity

d. Reflectivity + absorptivity

e. Absorptivity + transmissivity

  • c. Reflectivity

Q. Which is not the assumption in Fourier's equation of heat conduction?

a. Uniform area of cross-section

b. Steady heat flow

c. Homogeneous substance

d. Constant temperature difference

e. Thermal conductivity independent of temperature

  • a. Uniform area of cross-section

Q. Unsteady state of heat flow occurs in

a. Flow of heat through furnace walls

b. Flow of heat through insulated pipe with constant surface temperature

c. Annealing of castings

d. Flow of heat through refrigerator walls

e. None of the above

  • c. Annealing of castings

Q. Which of the following has higher thermal conductivity as compared to the remaining?

a. Air

b. Water

c. 37,500 kg

d. Hydrogen

e. Oxygen

  • b. Water

Q. Which of the following material has highest value of thermal diffusivity?

a. Steel

b. Concrete

c. Lead

d. Mineral wool

e. Wood

  • c. Lead

Q. The quantity of heat required to change the temperature of 1 gm of ice from -6?C to -5?C is known as

a. Freezing heat

b. Cold heat

c. Latent heat of freezing

d. Specific heat

e. Heat of vaporization

  • d. Specific heat

Q. For temperature below -40?C which one of the following substance can be used as thermometric substance

a. Alcohol

b. Pentane

c. Ether

d. Any of the above

e. None of the above

  • d. Any of the above

Q. The conditions under which three phases of matter can coexist in equilibrium, is known as

a. Common point

b. Triple point

c. Absolute point

d. Basic point

e. Standard point

  • b. Triple point
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