chemical engineering MCQs – Page 223

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 Review each marked answer and report any item that may be outdated or unclear.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

4441. Pick out the correct statement ?
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A. inder</strong>

B. e in temperature

C. Solid angle subtended by the finite surface at the radiating element is called the angle of

D. Higher is the temperature of the radiating body, higher is the wavelength of radiation

E. The wavelength corresponding to maximum mono-chromatic emissive power increases with

F. Logarithmic mean area is used for calculating the heat flow rate through a thick walled

4442. Pick out the wrong statement ?
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A. In case of heat transfer by purely forced convection, GR/Re 2 ? 1

B. The equivalent diameter of heat transfer for a duct of square cross-section (having each side as

C. med and detached from the heating surface

D. 216;x) is equal to 4x</strong>

E. Distillation process is not the same as evaporation

F. The effectiveness of nucleate boiling depends basically on the ease with which the bubbles are

4443. Fireclay bricks are used in the______________?
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A. Outer lining of L.D. converter

B. Hearth bottom of blast furnace

C. Coke oven walls

D. Coke ovens regenerator

4444. A liquid is in equilibrium with its vapor at its boiling point. On an average, the molecules in the liquid and gaseous phases have equal______________?
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A. Intermolecular forces of attraction

B. Kinetic energy

C. Total energy

D. Potential energy

4445. Pick out the correct statement ?
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A. Packed towers are generally preferred over plate towers, if the liquids have a foaming tendency

B. None of these

C. The pressure drop through the packed towers is generally more than the pressure drop through plate towers designed for same duty

D. When highly corrosive fluids are to be handled, the plate towers prove to be cheaper and easier to construct than packed tower

4446. A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter d. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to_____________________?
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A. d-1

B. d0.8

C. d-1.8

D. d-0.2

4447. The reverse process of fractional crystallisation is called__________________?
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A. Leaching

B. Differential distillation

C. Stripping

D. Absorption

4448. Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for_________________?
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A. Equal for all the three

B. Sphere

C. Cylinder

D. Cube

4449. Pick out the wrong unit conversion of heat transfer rate?
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A. 1 Watt = 1.163 kcal/hr

B. 1 kcal/hr= 1.163 Watt

C. 1 kcal/m2.hr = 0.3687 BTU/ft2.hr = 1.163 Watt/m2

D. 1 BTU/ft2.hr = 2.712 kcal/m2.hr

4450. Permeability of bricks is a measure of the___________________?
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A. Melting point

B. Refractoriness

C. Rate at which a fluid will pass through the pores

D. Expansion during heating

4451. If air (a non-condensing gas) is present in a condensing vapor stream, it will ______________ the condensation rate of vapor?
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A. Increase

B. Decrease

C. Increase the condensing film co-efficient as well as

D. Not affect

4452. The ratio of kinematic viscosity to thermal diffusivity is called the _______________ number?
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A. Stanton

B. Nusselt

C. Peclet

D. Prandtl

4453. Pick out the wrong statement?
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A. Unit of thermal conductance is W/K

B. None of these

C. Thermal conductance of a wall of thickness L, thermal conductivity k and heat flow area A is kL/A

D. Reciprocal of the resistance to heat flow is called thermal conductance

4454. Maximum alumina content in high alumina refractory can be as high as ____________ percent?
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A. 70

B. 50

C. 90

D. 30

4455. Pick out the wrong statement?
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A. The joint made by overlapping of one plate over the other, and then riveting the two plates together with two rows of rivets is called double riveted butt joint

B. Riveting provides a permanent fastening method

C. The efficiency of a riveted joint is the ratio of the strength of the riveted joint to the strength of the solid plate

D. Shank diameter of the rivets should be less than the size of the hole drilled in the plate for riveting

4456. Enthalpy of a vapor gas mixture may be increased by increasing the________________?
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A. Temperature at constant humidity

B. All A., B. & C.

C. Temperature and the humidity

D. Humidity at constant temperature

4457. A vapor whose partial pressure is less than its equilibrium vapor pressure is called a ______________ vapor?
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A. Supersaturated

B. Saturated

C. Superheated