chemical engineering MCQs – Page 204

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 Review each marked answer and report any item that may be outdated or unclear.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
4061. With increase in temperature, the thermal conductivity of a gas ___________________?
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A. Decreases

B. Remain same

C. Increases

D. May increase or decrease depending on the type of gas

4062. Multiple effect evaporation is generally recommended, when the______________________?
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A. Evaporation on small scale is to be done

B. Corrosive liquids are to be concentrated

C. Large scale evaporation of liquor is needed

D. Fuel is cheaply available

4063. The advantage of backward feed multiple effect evaporators over forward feed units is that___________________?
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A. There is no additional cost of pumping

B. Most concentrated liquid is at highest temperature

C. Equal heat transfer co-efficients exist in various effects

D. Heat sensitive material can be handled

4064. Film boiling occurs at ________________ pressure?
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A. Very high

B. Sub-atmospheric

C. Atmospheric

D. Negative

4065. The thermal radiation emitted by a body is proportional to Tn, where T is its absolute temperature. The value of n is exactly 4 for__________________?
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A. A black body

B. Polished bodies only

C. Black painted bodies only

D. All bodies
4066. Which of the following has the highest thermal conductivity ?
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A. Air

B. Silver

C. Water

D. Brick

4067. The separation of liquid droplets from the vapor is done by a/an _____________ in the evaporators?
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A. Entrainment separator

B. Steam ejector

C. Compressor

D. Vacuum pump

4068. In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is_________________?
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A. 0

B. Equal to the difference between hot and cold fluids inlet temperature

C. ?

D. Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature

4069. Film condensation is promoted on a/an _______________________ surface?
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A. Clean & smooth

B. Coated

C. Dirty

D. Oily

4070. Viscosity of gases ______________ with increase in temperature?
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A. Remain unaffected

B. Increase very rapidly

C. Increase slowly

D. Decrease slowly

4071. For a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would ?
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A. Increase

B. First decrease and then increase

C. First increase and then decrease

D. Decrease

4072. Intermittent tube cleaning is possible to be done in case of a _____________ evaporator?
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A. Horizontal tube

B. Calandria

C. Basket type
4073. Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?
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A. Condensate is corrosive in nature

B. Lower pressure drop through the exchanger is desired

C. Temperature of the incoming vapor is very high

D. Higher condensing film co-efficient is desired

4074. Fouriers law of heat conduction applies to _____________ surfaces?
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A. Isothermal

B. Non-isothermal

C. Both A. and B.

D. Neither A. and B.

4075. Presence of a non-condensing gas in a condensing vapour___________________?
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A. None of these

B. Is desirable to increase the film co-efficient

C. Increases the rate of condensation

D. Decreases thermal resistance

4076. A _____________ surface has the maximum thermal emissivity out of the following ?
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A. White & rough

B. White & smooth

C. Black & rough

D. Black & smooth

4077. A body is called grey if the monochromatic emissivity of the body is___________________?
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A. Unity

B. Zero

C. Different for all wavelengths

D. Same for all wavelengths
4078. Fouling factor used in the design of a multipass shell and tube heat exchanger is a_____________________?
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A. Non-dimensional factor

B. None of these

C. Conversion factor for individual film heat transfer co-efficient to overall heat transfer coefficient

D. Factor of safety
4079. Heat exchangers operating, when the asymptotic range is reached, ?
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A. Results in making part of the heating surface inactive

B. Provide very large heat transfer co-efficient

C. Results in abruptly increased velocity

D. None of these

4080. 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