chemical engineering Mcqs
6151. Function of air vessel provided in a reciprocating pump is to_________________?
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A. Reduce the danger of cavitation

B. Reduce discharge fluctuation

C. Increase the pump efficiency

D. Avoid the necessity of priming

6152. Periclase refractory contains mainly________________?
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A. CaO

B. MgO

C. Al2O3

D. SiO2

6153. Fireclay bricks is not used for lining the__________________?
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A. Roof of open hearth furnace

B. Gas producer

C. Bottom of hot metal mixer

D. Cupola

6154. The blades of a centrifugal impeller are said to be curved forward, if the ____________ of the motion of impeller blades?
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A. Inlet tip of a blade curves in a direction opposite to that

B. Outlet tip of a blade curves in a direction opposite to that

C. Inlet tip of a blade is towards the direction

D. Outlet tip of a blade is towards the direction
6155. Low specific speed of a pump implies that, it is a/an ______________ pump?
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A. Mixed flow

B. Centrifugal

C. None of these

D. Axial flow

6156. Fireclay bricks are used in the___________________?
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A. Furnaces allowed to cool frequently

B. Chimney linings

C. Flues

D. All A., B. and C.
6157. A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is___________________?
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A. 5

B. 28.2

C. 56.22

D. 14.1

6158. With the increase in depth, the hydrostatic pressure in an un-accelerated incompressible fluid (in a constant gravitational field) ?
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A. Decreases

B. Increases linearly

C. Remain constant

D. Increases exponentially

6159. Cermets are____________________?
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A. Composite material containing both ceramic & metallic constituents

B. Having high strength & resistance to high temperature

C. Used in space vehicles, missiles & nuclear energy plants

D. All A., B. and C.
6160. In panel test for spalling resistance, the average face temperature of panel assembly is maintained at ______________ C for 24 hours?
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A. 1600

B. 1000

C. 700

D. 2000

6161. Refractoriness under load (RUL) is the most important property for the refractory bricks_________________?
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A. At the hearth bottom of the furnace on which stock is placed

B. None of these

C. Used in the roof of the furnace

D. Used for furnace insulation

6162. Spray test determines the _____________ of refractories?
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A. Resistance to slag penetration

B. Resistance to CO attack

C. Permanent linear change

D. RUL

6163. Fireclay refractories have __________________?
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A. Low co-efficient of thermal expansion

B. Very high cost

C. Poor thermal spalling resistance

D. Tendency to expand unduly high during firing

6164. The ______________ pressure is measured by a static tube?
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A. None of these

B. Dynamic

C. Static

D. Total

6165. Furnace atmosphere for softening temperature determination of refractories (in which Seger Cones are placed) should be __________________?
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A. Neutral

B. Oxidising

C. Either A. or B.

D. Neither A. nor B.

6166. A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute ?
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A. 200

B. 750

C. 1000

D. 500
6167. Bottom of basic open hearth furnace are constructed of__________________?
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A. Dead burnt magnesite ramming mass

B. Porous fireclay bricks

C. Silicon carbide bricks

D. Semi-silica bricks

6168. A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is _____________ litres?
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A. 60

B. 660

C. 1.1

D. 600

6169. Refractory bricks with lower permeability is produced by using __________________?
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A. Finer grog size

B. Higher moulding pressure

C. All A., B. and C.

D. Higher firing temperature

6170. What is the shear rate at the pipe wall, in case of laminar flow of Newtonian fluids in a pipe of diameter D & length L incurring a pressure drop ?p with average velocity Vavg ?
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A. 4 Vavg/D

B. 8 Vavg/D

C. D ?p/4L

D. D ?p/8L

6171. ______________ bricks should not be used in oxidising atmosphere?
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A. Tar dolomite

B. Silica

C. Fireclay

D. Carbon
6172. Drag co-efficient for flow past immersed body is the ratio of _____________ to the product of velocity head and density?
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A. Shear force

B. Average drag per unit projected area

C. None of these

D. Shear stress

6173. Crushing strength of a refractory____________________?
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A. Decreases with increase in porosity

B. Increases with rise in service temperature

C. Is unaffected with change in service temperature

D. Decreases with rise in service temperature
6174. The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of _____________ fluid?
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A. Pseudo-plastic

B. Bingham plastic

C. Newtonian

D. Dilatent
6175. Presence of MgO in alumino-silicate refractories _______________ its refractoriness?
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A. Either A. or B.; depends on its quantity

B. Lowers

C. Increases

D. Does not affect

6176. Transition length for a turbulent fluid entering into a pipe is around _____________ times the pipe diameter?
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A. 5

B. 5000

C. 50

D. 500

6177. Outer combustion chamber of blast furnace stove is lined with _____________ bricks?
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A. Fireclay

B. Zirconia

C. Silica

D. Chrome magnesite

6178. What is the value of q for saturated liquid feed to a distillation column ?
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A. <1

B. 1

C. >1

D. 0

6179. In parallel pipe problems, the__________________?
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A. None of these

B. Total head loss is equal to the sum of the head losses through each pipe

C. Discharge is the same through all the pipes

D. Head loss is the same through each pipe
6180. Which one contains minimum percentage of SiO2 ?
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A. Aluminous firebrick

B. Semi-silica

C. Firebrick

D. Sillimanite
6181. Fanning friction factor for laminar flow of fluid in a circular pipe is____________________?
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A. Not a function of the roughness of pipe wall

B. Inversely proportional to Reynolds number

C. Both A. & B.

D. Neither A. nor B.

6182. In continuous fluidisation_________________?
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A. Solids are completely entrained

B. The pressure drop is less than that for batch fluidisation

C. Velocity of the fluid is very small

D. There is no entrainment of solids

6183. PCE value (Segar cone) of Superduty refractories is more than 33, which is equivalent to a temperature of ____________ C?
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A. 1670

B. 1520

C. 1630

D. 1730
6184. For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as_________________?
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A. d2

B. d? 2

C. d4

D. d

6185. Equivalent length of a pipe fitting is____________________?
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A. Independent of Reynolds number

B. Dependent on the length of the pipe

C. None of these

D. Dependent on Reynolds number
6186. High refractoriness of refractory bricks means, that it has a________________?
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A. High resistance to fusion

B. High spalling resistance

C. Low porosity

D. Low spalling resistance

6187. Slide gates in teeming laddie used for steel pouring in ingot moulds is lined with _____________ bricks?
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A. Silica

B. Semi-silica

C. Bakelite impregnated or fused periclase

D. Fireclay

6188. Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will _____________ the gas discharge pressure?
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A. Increase

B. Exponentially decrease

C. Decrease

D. Not change

6189. Which brick undergoes maximum shrinkage on drying ?
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A. Chromite bricks

B. Tar bonded dolomite bricks

C. Magnesite bricks

D. Fireclay bricks
6190. Porosity of fireclay refractories is _______________ percent?
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A. 10-May

B. 35-50

C. 10-25

D. 25-35

6191. In Newtons law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is___________________?
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A. 0.044

B. 4.4

C. 0.44

D. 44

6192. Test piece for determination of RUL of a refractory is heated in a/an____________________?
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A. Electric furnace

B. Oxidising atmosphere

C. Reducing atmosphere

D. Neutral atmosphere

6193. The maximum linear expansion of silica bricks during firing is about ______________ percent?
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A. 3.5

B. 0.5

C. 1

D. 2

6194. Permeability of bricks is a measure of the_________________?
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A. Refractoriness

B. Melting point

C. Expansion during heating

D. Rate at which a fluid will pass through the pores
6195. A pressure of 10 m head of water is equivalent to ______________ kN/m2?
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A. 98

B. 49

C. 196

D. 147

6196. Plunger pumps are used for__________________?
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A. None of these

B. Viscous mass

C. Higher pressure

D. Slurries

6197. Pick out the correct statement pertaining to transition/ entrance length in fluid flow ?
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A. 5. D.NRe

B. h that velocity profile does not change downstream, is called the transition length

C. Transition length for laminar flow of Newtonian fluids in a pipe of diameter d is equal to

D. All A., B. and C.

E. The length of entrance region of pipe, in which full development of fluid flow takes place

F. al to 50 D

6198. Walls, roofs & combustion chambers of annealing furnaces are made of ______________ bricks?
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A. Silica

B. Mullite

C. High duty fireclay

D. Carborundum

6199. Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to__________________?
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A. Slag attack

B. Thermal spalling

C. CO attack

D. Fusion under load

6200. In which of the following body shapes, the pressure drag is large compared to the friction drag ?
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A. None of these

B. Two dimensional body

C. Stream line body

D. Bluff body