chemical engineering MCQs – Page 194

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 Review each marked answer and report any item that may be outdated or unclear.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
3861. The equation, Nst = f/2, is the _____________ analogy?
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A. Prandtl

B. Reynolds

C. Colburn

D. None of these

3862. In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________?
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A. More

B. More or less; depends on the nature of solution

C. Less

D. Same

3863. The distance between the top of the slots and the liquid surface when the static liquid is just ready to flow over the overflow weir is called____________________?
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A. Skirt clearance

B. Downcomer liquid seal

C. Static submergence

D. None of these

3864. Heat flux, as defined in heat flow is analogous to _______________ in electricity flow?
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A. Resistance

B. Current

C. Voltage

D. None of these

3865. In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid___________________?
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A. Varies directly as the area and the LMTD

B. None of these

C. Varies as square of the area

D. Directly proportional to LMTD and inversely proportional to the area

3866. What is the minimum recommended ligament for square pitch arrangement in case of heat exchangers ?
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A. Equal to tube I.D

B. 6.5 cms

C. Equal to tube O.D

D. 6.5 mm
3867. Which one gives the monochromatic emissive power for black body radiation ?
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A. Stefan-Boltzmann law

B. Plancks law

C. Wiens law

D. Kirchhoffs law

3868. A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of__________________?
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A. 20.8

B. 20.5

C. 2

D. 20.2

3869. Needle valves are generally not used for___________________?
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A. Very accurate flow control

B. High pressure throttling service

C. Smaller sizes of pipe

D. Very large diameter pipes
3870. In a shell and tube heat exchanger, square pitch compared to triangular pitch__________________?
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A. None of these

B. Gives a higher shell side pressure drop

C. Can pack more surface area into a shell of given diameter

D. Gives a lower shell side pressure drop

3871. Theoretically calculated diameter of the stripping section of the continuous rectification column is ______________ that of the enriching section?
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A. Same as

B. Either more or less (depending upon relative volatility

C. More than

D. Less than

3872. Maximum heat transfer rate is obtained in ______________ flow?
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A. Turbulent

B. Transition region

C. Creeping

D. Laminar

3873. Maximum heat transfer rate is achieved in _____________ flow?
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A. Laminar

B. Co-current

C. Counter-current

D. Turbulent
3874. In pipe flow, heat is transferred from hot wall to the liquid by__________________?
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A. Free and forced convection

B. Conduction only

C. Forced convection and conduction

D. Forced convection only

3875. Stefan-Boltzmann law which describes the radiation heat transfer states that, it is proportional to (where, t = temperature in C T = absolute temperature in K) ?
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A. 1/T4

B. T4

C. t4

D. 1/t4

3876. Pick out the wrong statement pertaining to the design of the distillation column?
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A. None of these

B. idue build up

C. Generally, a skirt clearance of 0.5? to 1.5? is recommended to prevent plugging of the slots by

D. If sufficient slot area is not provided, the gas may pass through the skirt clearance

E. The purpose of the slot is to disperse the gas into the liquid in the form of small bubbles

3877. Heat sensitive materials can be concentrated in an evaporator employing_______________?
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A. Vacuum

B. High pressure

C. High residence time

D. None of these

3878. Fruit juice (a heat sensitive material) can be concentrated in a ____________ evaporator?
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A. None of these

B. Long tube

C. Falling film

D. High pressure

3879. Maximum plate efficiency is achieved in case of ______________ flow?
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A. Cross

B. Split

C. Cascade

D. Reverse

3880. Brass valves are usually made for pipe sizes ______________ inches?
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A. ? 1

B. ? 2

C. > 3.5

D. > 2.5