chemical engineering heat transfer chemical engineering MCQs – Page 4

Practise multiple-choice questions from chemical engineering heat transfer chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering heat transfer chemical engineering Mcqs
61. When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as ___________________ boiling?
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A. Transition

B. Nucleate

C. Film

D. Pool

62. The rate of emission of radiation by a body does not depend upon the__________________?
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A. Nature of the surface

B. Surface temperature of the body

C. Shape and porosity of the body

D. Wavelength of radiation

63. In sub-cooled boiling ?
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A. Bubbles from heating surface are absorbed by the mass of the liquid

B. Temperature of the heating surface is more than the boiling point of the liquid

C. Very large vapour space is necessary

D. Temperature of the heating surface is less than the boiling point of the liquid

64. The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is ________________?
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A. 2

B. 2-Jan

C. 1/4

D. 4

65. The overall resistance for heat transfer through a series of flat resistance, is the _____________ of the resistances?
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A. Product

B. Sum

C. Geometric mean

D. Average

66. Kirchoffs law is applicable to________________?
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A. Monochromatic radiation only

B. Total radiation only

C. Both A. and B.

D. Only volumes and not to surfaces

67. If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law?
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A. Hyperbolic

B. Linear

C. Logarithmic

D. Parabolic
68. The driving potential for the crystal growth during crystallisation is the _______________ of the solution?
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A. Super-saturation

B. Density

C. Concentration

D. Viscosity

69. Grashoff number is given by________________?
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A. gD2??t?/?2

B. gD3??tP2/?

C. gD3.?.?t?2/?2

D. gD2??tP2?

70. Heat flux, as defined in heat flow is analogous to _______________ in electricity flow?
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A. None of these

B. Voltage

C. Current

D. Resistance

71. In Fouriers law, the proportionality constant is called the______________________?
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A. Heat transfer co-efficient

B. Thermal conductivity

C. Stefan-Boltzmann constant

D. Thermal diffusivity

72. What is the logarithmic mean of r1 and r2 ?
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A. (r1 r2)/ln(r2/r1)

B. (r2 r1)/ln(r1/r2)

C. (r1 r2)/-ln(r1/r2)

D. (r1 r2)/ln(r1/r2)
73. In a shell and tube heat exchanger, floating head is used for _________________?
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A. Low pressure drop

B. High heat transfer co-efficient

C. Less corrosion of tubes

D. Large temperature differentials
74. Cp?/K is termed as the ______________ number?
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A. Stanton

B. Nusselt

C. Prandtl

D. Grashoff

75. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is__________________?
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A. 4.36

B. Dependent on NRe only

C. 2.36

D. 120.36

76. A steel sphere of radius 0.1 m at 400K is immersed in an oil at 300K. If the centre of the sphere reaches 350K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions? Assume that the conductive heat transfer co-efficient is infinitely large ?
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A. 5 minutes

B. 20 minutes

C. 10 minutes

D. 40 minutes

77. Heat exchanger tubes are never made of_________________?
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A. Plain carbon steel

B. Copper

C. Stainless steel

D. Lead
78. Economy of a multiple effect evaporator depends upon the _____________________?
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A. Heat balance consideration

B. Rate of heat transfer

C. Both A. and B.

D. Neither A. nor B.

79. Which of the following parameters of the fluid is not very important, while deciding its route in a shell and tube heat exchanger ?
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A. Density

B. Corrosiveness & fouling characteristics

C. Pressure

D. Viscosity

80. Steam trap is used to_________________?
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A. Remove water resulting from partial condensation of steam

B. Stop the supply of steam

C. Condense the steam flowing in the pipeline

D. None of these