chemical engineering Mcqs
6051. The equation relating friction factor to Reynold number, f-0.5 = 4 loge (NRe/?f)-0.4, is called the _____________ equation?
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A. Nikuradse

B. Blasius

C. Von-Karman

D. Colebrook

6052. Sillimanite is a _____________ refractory?
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A. Basic

B. Neutral

C. Insulating

D. High alumina
6053. Purpose of relief valve in a reciprocating pump is to___________________?
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A. Facilitate unidirectional flow of liquid

B. Control the rate of discharge

C. Protect the pump against developing excessive pressure

D. Reduce the discharge pressure

6054. The largest consumer of refractories is the _______________ industry?
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A. Power

B. Metallurgical

C. Fertiliser

D. Cement

6055. Chromite refractories are_____________________?
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A. Acidic refractory

B. Fired at a temperature of 600C only

C. Basic refractory

D. Neutral refractory
6056. Pascal law is not applicable for a/an ________________________ fluid?
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A. Static

B. None of these

C. Accelerating frictionless

D. Uniformly moving

6057. With decrease in porosity, the ______________ of the refractories decreases?
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A. Strength

B. Spalling resistance

C. Thermal conductivity

D. None of these

6058. As per Newtons law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to (where, ? = fluid viscosity) ?
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A. 1/?2

B. ?2

C. 1/?

D. ?
6059. For steady ideal fluid flow, the Bernoullis equation states that the_________________?
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A. Energy is constant along a stream line, but may vary across stream lines

B. None of these

C. Velocity is constant along a stream line

D. Energy is constant throughout the fluid

6060. Spalling resistance of a refractory cannot be increased by ____________________?
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A. Making it denser

B. Decreasing its thermal co-efficient of expansion

C. Using a coarser grog during its manufacture

D. Increasing its porosity

6061. In laminar flow through a round tube, the discharge varies ______________________?
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A. Inversely as the pressure drop

B. As the square of the radius

C. Linearly as the viscosity

D. Inversely as the viscosity
6062. Fireclay bricks are not used in the_____________________?
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A. Hot blast stove

B. Blast furnace

C. Wall of coke oven

D. Cupola

6063. Newtons law of viscosity relates the____________________?
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A. Shear stress and velocity

B. Pressure gradient and rate of angular deformation

C. Velocity gradient and pressure intensity

D. Shear stress and rate of angular deformation in a fluid
6064. Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newtons law of viscosity. (II) Newtons second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to boundary. (V) Fluid cannot penetrate a boundary?
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A. II, IV, V

B. I, II, III

C. II, III, V

D. I, II, V

6065. Which is required in an insulating refractory ?
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A. High thermal conductivity

B. Low porosity

C. Both A. and B.

D. Neither A. nor B.
6066. Air vessel fitted to a reciprocating pump____________________?
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A. Results in non-uniform discharge

B. Increases the work done

C. Causes cavitation

D. Decreases the work done
6067. A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit E. to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062 ?
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A. 11.8 m

B. 11 m

C. 30 m

D. 10 m

6068. Which of the following equations is valid for laminar flow of a fluid through packed bed ?
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A. Fanning equation

B. Blake-Plummer equation

C. Hagen-Poiseuille equation

D. Kozeny Karman equation
6069. Pressure co-efficient is the ratio of pressure forces to __________________________ forces?
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A. Gravity

B. None of these

C. Viscous

D. Inertial
6070. Spalling tendency of refractories is reduced by increasing its_________________?
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A. Thermal conductivity

B. Strength

C. Specific gravity

D. Porosity
6071. With increase in molecular weight of the gas, the head developed by a centrifugal compressor will________________?
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A. Unpredictable

B. Decrease

C. Remain same

D. Increase

6072. Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, because of its_______________?
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A. High thermal conductivity

B. None of these

C. Non-wetting characteristic

D. High crushing strength

6073. Pure oxide refractories are generally monocrystalline in nature and are self bonded _______________ bricks are generally used as moderator in nuclear reactors?
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A. Corundum

B. Thoria

C. Beryllia

D. Carborundum

6074. Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as _____________ percent?
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A. 90

B. 80

C. 70

D. 55

6075. Forces acting on a particle settling in fluid are _____________ forces?
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A. Gravitational & buoyant

B. Centrifugal & drag

C. External, drag & viscous

D. Gravitational or centrifugal buoyant drag
6076. Potential flow is characterised by the___________________?
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A. One in which dissipation of mechanical energy into heat occurs

B. Irrotational and frictionless flow

C. Irrotational and frictional flow

D. Formation of eddies within the stream

6077. Fusion point of a basic refractory material is__________________?
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A. Not affected by the addition of acid oxides

B. Always less than 1000C

C. Increased by the addition of acid oxides

D. Reduced by the addition of acid oxides
6078. Fireclay refractories____________________?
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A. Shrink during firing

B. Combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming

C. Are not resistant to the action of basic slags

D. ible aluminates silicates etc

E. All A., B. and C.
6079. The highest melting pure oxide (m.p. > 3000C)is___________________?
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A. Beryllia

B. Zirconia

C. Alumina

D. Thoria
6080. In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes_______________?
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A. More than liquid vapor pressure

B. More than atmospheric pressure

C. Less than liquid vapor pressure

D. Less than atmospheric pressure

6081. In a fluidised bed reactor___________________?
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A. Segregation of the solids occurs

B. Temperature is more or less uniform

C. Temperature gradients are very high

D. Hot spots are formed

6082. A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by________________?
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A. Decreasing the size of the inlet pipe

B. Increasing the size of the inlet pipe

C. Lowering the pump position

D. Both B. and C.
6083. Fireclay bricks are not used in the _________________?
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A. Combustion chamber of B.F. stoves

B. Beehive coke oven

C. By-product coke oven walls

D. Coke oven regenerators

6084. Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for _____________ bricks?
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A. Silica

B. Very low alumina

C. Fireclay

D. Dolomite

6085. Sillimanite (Al2O3.SiO2) refractory, which is a neutral refractory, is not used in________________?
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A. Pottery furnace

B. Gas retorts

C. Glass melting furnace

D. Crucibles

6086. In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow ?
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A. Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

B. Water discharge from a vertical vessel in which constant level is maintained

C. Water flow in the suction and discharge pipe of a reciprocating pump

D. Discharge of water by a centrifugal pump being run at a constant rpm

6087. Magnesite refractories are used for the construction of those furnaces, which are________________?
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A. Not required to resist the corrosive action of basic slag

B. Not subjected to fluctuation in temperature

C. Used for raising & maintaining high temperature

D. Both B. and C.
6088. Cold crushing strength of ordinary fireclay brick is about 950 kg/cm2. On exposure to a temperature of about 1500C, its crushing strength may come down to as low as ______________ kg/cm2?
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A. 250

B. 450

C. 65

D. 150

6089. Carborundum used for making crucibles for melting non-ferrous metals is chemically________________?
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A. Crystalline magnesia

B. Zirconium sulphate

C. Silicon nitride

D. Silicon carbide
6090. What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate ?
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A. 1.5

B. 0.5

C. 1

D. 2

6091. Which is the stable form of silica between 1470C and the melting point 1713C ?
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A. Tridymite

B. Cristobalite

C. Quartz

D. None of these

6092. Which of the following facilitates close control of flow of fluids ?
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A. Butterfly valve

B. Globe valve

C. Check valve

D. Gate valve

6093. 10 to 30% magnesite is added to Chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the _____________ of Chromite?
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A. Crushing strength

B. Refractoriness

C. Spalling resistance

D. Resistance to slag

6094. Which is not an acidic refractory ?
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A. High alumina refractory

B. Carbon black

C. Silica

D. Fireclay

6095. Which is an acidic refractory ?
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A. Magnesite

B. Fireclay

C. Chrome magnesite

D. Dolomite

6096. Which of the following is a Newtonian fluid ?
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A. Rubber latex

B. Sewage sludge

C. Non-colloidal solution

D. Quicksand

6097. One poise (unit of absolute/dynamic viscosity) is equivalent to one_____________________?
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A. gm/cm. sec

B. m2/sec

C. gm/cm2. sec

D. cm2/sec

6098. I.D. of 1/4? schedule 40 pipe is 0.364?. I.D. of a 1/2? schedule 40 pipe would be ______________ inch?
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A. 0.5

B. 0.474

C. 4.728

D. 0.622
6099. Cold crushing strength of fireclay bricks is about ______________ kgf/cm2?
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A. 200-400

B. 500-1000

C. 100-150

D. 50-100

6100. Chromite refractories are used in_______________?
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A. Bottom of soaking pits

B. Between acid & basic linings in basic open hearth furnaces to prevent their chemical action

C. h each other

D. Both A. & B.

E. Neither A. and B.