chemical engineering MCQs – Page 197

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs

3921. A shell may by termed as thin if its thickness to diameter ratio is less than 0.1. The factor which can be neglected in the calculation of membrane stresses is________________?
0

A. Bending

B. Deformation

C. Shear

D. Elongation

3922. In case of 1.5? heat exchanger tubes, the inside flow area _____________ with decrease in BWG?
0

A. Remains same

B. Decreases

C. None of these

D. Increases

3923. View factor is important in heat transfer by_____________________?
0

A. Steady state conduction

B. Forced convection

C. Natural convection

D. Radiation

3924. In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid _______________?
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A. None of these

B. And the wall is not related

C. And the wall are proportional to individual resistances

D. Is inversely proportional to the resistance across which the drop occurs

3925. It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30C. The boiling point of the solution is 110C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is____________________?
0

A. 6.12 105

B. 9.08 105

C. 7.24 105

D. 3.06 105

3926. For a laminar flow of fluid in a circular tube, h1 is the convective heat transfer co-efficient at velocity V1. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is________________?
0

A. 0.574 h1

B. 0.794 h1

C. 1.26 h1

D. 1.741 h1

3927. Nucleate boiling is promoted ___________________?
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A. On polished surfaces

B. None of these

C. In the absence of agitation

D. On rough surfaces

3928. Dropwise condensation is promoted on a/an ______________ surface?
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A. Glazed

B. Coated

C. Oily

D. Smooth

3929. What is the emissivity of a black body ?
0

A. 1

B. 0.5

C. 0

D. 0.9

3930. Water is normally used as a coolant in the heat exchange equipments mainly because of its___________________?
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A. High fluidity

B. Abundance & high heat capacity

C. Low density

D. Low viscosity

3931. Tubes are held between top and bottom tube sheets in Calandria type evaporator by keeping_________________?
0

A. Both the tube sheets fixed

B. Both the tube sheets floating

C. The top tube sheet floating and bottom tube sheet fixed

D. The top tube sheet fixed and the bottom tube-sheet floating

3932. Which of the following has the lowest Prandtl number ?
0

A. Water

B. Molten sodium (a coolant used in fast breeder reactor)

C. Transformer oil

D. Dilute H2SO4

3933. Pick out the wrong statement about routing of fluids in a shell and tube heat exchanger ?
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A. The corrosive and fouling fluid should be preferably routed through the tubes

B. Higher pressure fluid stream should be routed through the shell side

C. The viscous fluid should be routed through the shell side

D. Lower flow rate fluid should be routed through the shell side

3934. Welded joint efficiency in the design of chemical process equipment is taken as_________________?
0

A. 0.55

B. 0.95

C. 0.85

D. 0.75

3935. Souders Brown equation given by, U = Kv ?(?l ?v)/?v, is used for the calculation of the ______________ in a continuous distillation column?
0

A. Tray pressure drop

B. Residence time in the downcomer for the disengagement of entrained vapour

C. Diameter of the bubble cap column

D. Diameter of the sieve plate column

3936. Conductance is given by (where, x = thickness, A = heat flow area, K = thermal conductivity.)?
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A. K/Ax

B. x/KA

C. KA/x

D. A/Kx

3937. Prandtl number for most of dry gases is about________________?
0

A. 0.72

B. 150

C. 70

D. 0.001

3938. Radiator of an automobile engine is a ______________ type of heat exchanger?
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A. Co-current

B. Direct contact

C. Counter-current

D. Cross-current

3939. Cp?/K is termed as the ______________ number?
0

A. Stanton

B. Grashoff

C. Nusselt

D. Prandtl

3940. For a given fluid, as the pipe diameter increases, the pumping cost ____________________?
0

A. Increases

B. May increase or decrease depending upon whether the fluid is Newtonian or non-Newtonian

C. Remain unaffected

D. Decreases

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