chemical engineering Mcqs
6351. Ratio of inertial forces to surface tension forces is called the _____________ number?
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A. Froude

B. Weber

C. Mach

D. Euler

6352. The capillary rise of mercury is maximum in glass tube of dia _____________ mm?
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A. 0.5

B. 5

C. 1

D. 2

6353. Vane anemometer __________________?
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A. ersed</strong>

B. None of these

C. Rotates an element at a speed determined by the velocity of the fluid in which the meter is

D. Is a variable head meter

E. Is an area meter

6354. A bed of spherical particles (specific gravity 2.5) of uniform size 1500 ?m is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Erguns equation for the above fluid-particle system (in SI units) is given below: ? P/L = 375 103 VOM + 10.94 106 V2 OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?
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A. 0.5

B. 0.2

C. 0.7

D. 0.8

6355. In hindered settling, the particles are_________________________?
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A. None of these

B. Placed farther from the wall

C. Near each other

D. Not affected by other particles and the wall

6356. Pressure drop in a packed bed for laminar flow is given by the ______________ equation?
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A. Blake-Plummer

B. Kozeny-Carman

C. Levas

D. Fanning friction factor

6357. The hydrodynamic and thermal boundary layers will merge, when ____________________?
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A. Schmidt number tends to infinity

B. Nusselt number tends to infinity

C. Archimedes number is greater than 10000

D. Prandtl number is one
6358. Drag co-efficient for motion of spherical particles in a stationary fluid in the stokes law range is_________________?
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A. 64/NRe,P

B. 48/NRe,P

C. 24/NRe,P

D. 16/NRe,P

6359. Nominal size of a pipe is an indication of its ______________ diameter?
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A. Outer

B. None of these

C. Approximate

D. Inner

6360. The fluid property, due to which, mercury does not wet the glass is__________________?
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A. Surface tension

B. Viscosity

C. Adhesion

D. Cohesion

6361. The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s) ?
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A. 0.44

B. 0.24

C. 24

D. 24000

6362. A rectangular surface 3? 4?, has the lower 3 edge horizontal and 6? below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force on one side of the surface is (where, y = specific weight of water) ?
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A. 48y

B. 39.6y

C. 58y

D. 49.2y

6363. Centrifugal compressors compared to reciprocating compressors__________________?
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A. Have lower operating costs

B. Have quieter operation

C. All A., B. and C.

D. Require less space

6364. Centrifugal pump cant be used to pump _____________________?
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A. Moderately viscous vegetable oil used in soap industry

B. Thick molten soap at 80C

C. None of the above

D. Molten sodium (used as a coolant in Fast Breeder Reactor)

6365. The pressure and power requirement of a gas fan at constant speed & capacity varies ____________ the gas density?
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A. Directly as

B. As square of

C. Inversely as

D. Inversely as square root of

6366. Hot wire anemometer is used to measure the_________________?
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A. Velocity of gases

B. Pressure of liquids

C. Temperature of liquids

D. Velocity of liquids

6367. The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet ?
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A. P, Rand S

B. P, Q and R

C. P and R

D. R and S

6368. With increase in pump speed, its NPSH requirement_________________?
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A. Decreases

B. Increases

C. Can either increase or decrease; depends on other factors

D. Remains unaltered

6369. A Venturimeter measures the___________________?
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A. Pressure

B. Point velocity

C. None of these

D. Velocity head

6370. Hydraulic diameter for non-circular ducts is equal to ___________ times the area of flow divided by the perimeter?
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A. Two

B. Three

C. Four

D. Eight

6371. In area meter (e.g., Rotameter), with increase in the fluid flow rate, the___________________?
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A. Area through which fluid flows does not vary

B. Pressure drop is almost constant

C. None of these

D. Pressure drop increases linearly

6372. One dimensional flow implies________________________?
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A. A flow which does not account for changes in transverse direction

B. Unsteady uniform flow

C. Steady uniform flow

D. Flow in a straight line

6373. The head developed by a centrifugal pump is largely determined by the____________________?
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A. Vapour pressure of the liquid

B. Angle of the vanes and the speed of the tip of the impeller

C. Nature of the liquid being pumped

D. Power of the pump

6374. The range of a particular Rotameter can be increased by__________________?
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A. Decreasing the diameter of the float

B. Use of floats of different densities

C. No means

D. Increasing the diameter of the float

6375. Bernoullis equation for steady, frictionless, continuous flow states that the ______________ at all sections is same?
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A. None of these

B. Velocity head

C. Total energy

D. Total pressure

6376. Kinetic energy of fluid per unit weight represented by the velocity head is given by___________________?
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A. v2/2gc

B. 2v2/gc

C. ?.v2/2gc

D. ?v2/gc

6377. Diaphragm pumps are used to transport_________________?
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A. Solids

B. Slurries

C. Fluids

D. Liquids

6378. With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss_______________?
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A. Remain constant

B. Increases

C. Increases linearly

D. Decreases

6379. Brownian movement is prominent in the particle size range of _____________ microns in case of settling of a particle in a fluid?
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A. 100 to 1000

B. 0.01 to 0.10

C. 2 to 3

D. 200 to 300

6380. For the same terminal conditions and fitting size, the least friction loss is incurred in a/an ?
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A. 90bend

B. 45 elbow

C. Union

D. T-joint

6381. Discharge from a 24 inch pipe of water at 10 ft/sec will be _____________ ft3/sec?
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A. 7.65

B. 125.6

C. 32.36

D. 48.22

6382. To handle smaller quantity of fluid at higher discharge pressure, use a ______________ pump?
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A. Volute

B. Rotary vacuum

C. Reciprocating

D. Centrifugal

6383. Which of the following denotes the effect of compressibility in fluid flow ?
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A. Weber number

B. Euler number

C. Mach number

D. Reynolds number

6384. In which of the following cases, it is possible for flow to occur from low pressure to high pressure ?
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A. Flow of liquid upward in a vertical pipe

B. Impossible in a constant cross-section conduit

C. Flow through a converging section

D. Flow of air downward in a pipe

6385. Minimum porosity for fluidisation is____________________?
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A. That corresponding to static bed

B. The porosity of the bed when true fluidisation begins

C. Less than that of the static bed

D. That corresponding to completely fluidised bed

6386. A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of _______________ shape?
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A. Trapezoidal

B. Rectangular

C. Circular

D. Triangular

6387. The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for ____________ fluid?
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A. Bingham plastic

B. Dilatent

C. Newtonian

D. Pseudo-plastic
6388. Potential flow is the flow of______________?
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A. Incompressible fluids with no shear

B. Compressible fluids with shear

C. Compressible fluids with no shear

D. Incompressible fluids with shear

6389. In a fully turbulent flow (Re > 105) in a pipe of diameter d, for a constant pressure gradient, the dependence of volumetric flow rate of an incompressible fluid is_______________?
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A. d2

B. d2.5

C. d

D. d4

6390. 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, then the new head will be ______________ metres?
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A. 4

B. 8

C. 2

D. 5.5

6391. Capacity of a rotary gear pump can be varied by__________________?
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A. Changing the speed of rotation

B. Bypassing liquid from the suction or discharge line

C. All A., B. and C.

D. Bleeding air into suction

6392. The pressure head on sudden contraction in a horizontal pipe is converted into the _____________ head?
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A. Elevation

B. Velocity

C. Both A. & B.

D. Neither A. nor B.

6393. Which of the following conditions must be satisfied for lift force to be developed ?
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A. The body should be bluff body

B. The main stream velocity must approach the velocity of sound in that fluid medium

C. The body should be stream lined

D. Circulation around the body is essentially required
6394. A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is________________?
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A. None of these

B. 3.7 KPa

C. 2.94 KPa

D. 4.4 KPa
6395. For very low pressure and high discharge rate, the compressor used is a/an ______________ compressor?
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A. Rotary

B. None of these

C. Reciprocating

D. Axial

6396. Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, ? = surface tension of mercury)____________________?
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A. 1/d

B. 1/?

C. d

D. ?
6397. The line of action of the buoyant force acts through the____________________?
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A. Centroid of the volume of any floating body

B. Centre of gravity of a submerged body

C. None of these

D. Centroid of the displaced volume of fluid
6398. A centrifugal pump is called a turbine pump, if it is having a_________________?
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A. Rotating vaned volute

B. Vaned diffusion casing

C. Turbine type impeller

D. None of these

6399. The co-efficient of discharge of an orificemeter is a function of ________________?
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A. Reynolds number at the orifice

B. Ratio of orifice dia to pipe dia

C. Both A. and B.

D. None of the above parameters, and has a constant value of 0.61

6400. Non-colloidal solution is an example of the _______________ fluid?
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A. Pseudo-plastic

B. Non-Newtonian

C. Dilatent

D. Newtonian