Railways NTPC (Technical Ability) Fluid Mechanics and Machinery Question Bank

done Fluid Mechanics and Machinery Total Questions - 50

• question_answer1)
  The velocity components in the x and y direction of a two dimensional potential flow are u and v respectively, then \[\frac{\partial u}{\partial x}\] is equal to
  A)
   \[\frac{\partial v}{\partial x}\]                             done clear
  B)
   \[-\frac{\partial v}{\partial x}\] done clear
  C)
   \[\frac{\partial v}{\partial y}\]                             done clear
  D)
   \[-\frac{\partial v}{\partial y}\] done clear
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• question_answer2)
  In a two-dimensional velocity field with velocities u and v along the x and y directions respectively, the convective acceleration along the x-direction is given by
  A)
   \[u\frac{\partial u}{\partial x}+v\frac{\partial u}{\partial y}\]        done clear
  B)
   \[u\frac{\partial u}{\partial x}+v\frac{\partial u}{\partial y}\] done clear
  C)
   \[u\frac{\partial v}{\partial x}+v\frac{\partial u}{\partial y}\]                    done clear
  D)
   \[v\frac{\partial u}{\partial x}+u\frac{\partial u}{\partial y}\] done clear
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• question_answer3)
  For the continuity equation given\[\nabla \centerdot \overrightarrow{v}=0\]to be valid, when\[\overrightarrow{v}\]is the velocity vector, which one of the following is a necessary condition?
  A)
   Steady flow                   done clear
  B)
   Irrigational flow done clear
  C)
   Invescid flow                 done clear
  D)
   Incompressible flow done clear
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• question_answer4)
  A streamline and an equipotential line in a flow field
  A)
   are parallel to each other done clear
  B)
   are perpendicular to each other done clear
  C)
   intersect at an acute angle done clear
  D)
   are identical done clear
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• question_answer5)
  Biot number signifies the ratio of
  A)
   convective resistance in the fluid to conductive resistance in the solid done clear
  B)
   conductive resistance in the solid convective resistance in the fluid done clear
  C)
     inertia force to viscous force in the fluid done clear
  D)
   buoyancy force to viscous force in the fluid done clear
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• question_answer6)
  A flow field which has only convective acceleration is
  A)
   a steady uniform flow done clear
  B)
   an unsteady uniform flow done clear
  C)
   a steady non-uniform flow done clear
  D)
   an unsteady non-uniform flow done clear
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• question_answer7)
  Length of mercury column at a place at an altitude will vary with respect to that at ground in a
  A)
   linear relation done clear
  B)
   hyperbolic relation done clear
  C)
   parabolic relation done clear
  D)
   manner first slowly and then steeply done clear
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• question_answer8)
  A type of flow in which the fluid particles while moving in the direction of flow rotate about their mass centre, is called
  A)
   steady flow                   done clear
  B)
   uniform flow done clear
  C)
   laminar flow                  done clear
  D)
   rotational flow done clear
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• question_answer9)
  Buoyant force is
  A)
   resultant of up thrust and gravity forces acting on the body done clear
  B)
   resultant force on the body due to the fluid surrounding it done clear
  C)
   resultant of static weight of body and dynamic thrust of fluid done clear
  D)
   equal to the volume of liquid displaced by the body done clear
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• question_answer10)
  The capillary rise in a narrow two-dimensional slit of width 'w' is
  A)
   half of that in a capillary tube of diameter 'w' done clear
  B)
   two-third of that in a capillary tube of diameter ?w? done clear
  C)
   one-third of that in a capillary tube of diameter 'w' done clear
  D)
   one-fourth of that in a capillary tube of diameter 'w' done clear
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• question_answer11)
  Which of the following flow measurement device is independent of density?
  A)
   Electro ? magnetic flow meter done clear
  B)
   Orifice plate done clear
  C)
   Turbine meter done clear
  D)
   Venturi-meter done clear
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• question_answer12)
  The cause of turbulence in fluid flow may be
  A)
   high Reynold number done clear
  B)
   abrupt discontinuity in velocity distribution done clear
  C)
   critical Reynold number done clear
  D)
   existence of velocity gradient without abrupt discontinuity done clear
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• question_answer13)
  For an irrational flow the equation \[\frac{{{\partial }^{2}}\phi }{\partial {{x}^{2}}}+\frac{{{\partial }^{2}}\phi }{\partial {{y}^{2}}}\]is known as
  A)
   Bernoulli's equation done clear
  B)
   Cauchy Riemann's equation done clear
  C)
   Euler's equation done clear
  D)
   Laplace equation. done clear
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• question_answer14)
  A control volume refers to
  A)
   a closed system done clear
  B)
   a specified mass done clear
  C)
   an isolated system          done clear
  D)
   a fixed region in space done clear
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• question_answer15)
  Pseudo plastic is a liquid for which
  A)
    dynamic viscosity decreases as the rate of shear increases done clear
  B)
   Newton's law of viscosity holds good done clear
  C)
    dynamic viscosity increases as the rate of shear increases done clear
  D)
    dynamic viscosity increases with the time for which shearing forces are applied. done clear
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• question_answer16)
  An ideal fluid is defined as the fluid which:
  A)
   is compressible done clear
  B)
   is in compressible done clear
  C)
   is in compressible and non-viscous done clear
  D)
   has negligible surface tension done clear
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• question_answer17)
  Which of the following is the unit of kinematic viscosity?
  A)
   \[N-S/{{m}^{2}}\]                   done clear
  B)
   \[{{m}^{2}}/s\] done clear
  C)
   \[kg/s{{m}^{2}}\]                    done clear
  D)
   \[m/kg-s\] done clear
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• question_answer18)
  Poise is the unit of:
  A)
   dynamic viscosity          done clear
  B)
   kinematic viscosity done clear
  C)
   mass density                 done clear
  D)
   velocity gradient done clear
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• question_answer19)
  Surface tension is a phenomenon because of:
  A)
   viscous forces only done clear
  B)
   Adhesion between liquid and solid molecules done clear
  C)
   Difference in magnitude between the forces due to adhesin and cohesion done clear
  D)
   cohesion only done clear
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• question_answer20)
  In case of a static fluid:
  A)
   only normal stresses can exist done clear
  B)
   linear deformation is small done clear
  C)
   fluid pressure is zero done clear
  D)
   resistance to shear stress is small done clear
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• question_answer21)
  Gauge pressure is equal to :
  A)
   absolute pressure + atmospheric pressure done clear
  B)
   absolute pressure \[-\] atmospheric pressure done clear
  C)
   atmospheric pressure \[-\] absolute pressure done clear
  D)
   atmospheric pressure \[-\] vaccum done clear
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• question_answer22)
  Compressibility\[(\beta )\]is equal to: (If k is bulk modulus)
  A)
   \[\beta =\frac{1}{k}\]                done clear
  B)
   \[\beta =k\] done clear
  C)
   \[\beta =\frac{1}{{{k}^{2}}}\]            done clear
  D)
   \[\beta ={{k}^{2}}\] done clear
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• question_answer23)
  Kinematic viscosity is equal to:
  A)
   Dynamic viscosity \[\times \] density done clear
  B)
   \[\frac{\text{Dynamic}\,\,\text{viscosity}}{\text{Density}}\] done clear
  C)
   \[\frac{\text{Density}}{\text{Dynamic}\,\,\text{viscosity}}\] done clear
  D)
   \[\frac{\text{1}}{\text{Dynamic}\,\,\text{viscosity}\,\,\text{Density}}\] done clear
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• question_answer24)
  Void ratio does not depend upon :
  A)
   Liquid limit                   done clear
  B)
   Volume done clear
  C)
   Bulk volume                  done clear
  D)
   Porosity done clear
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• question_answer25)
  The difference of pressure between inside and outside of a liquid drop is
  A)
   \[\Delta P=T\times r\]                 done clear
  B)
   \[\Delta P=\frac{T}{r}\] done clear
  C)
   \[\Delta P=\frac{T}{2r}\]                       done clear
  D)
   \[\Delta P=\frac{2T}{r}\] done clear
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• question_answer26)
  Falling drops of water become spherical in shape due to the property of:
  A)
   adhesion                       done clear
  B)
   cohesion done clear
  C)
   surface tension   done clear
  D)
   viscosity done clear
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• question_answer27)
  Capillary action is due to:
  A)
   viscosity of liquid done clear
  B)
   cohesion of liquid particles done clear
  C)
   surface tension done clear
  D)
   None of these done clear
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• question_answer28)
  Hydrostatic low states that the rate of increase of pressure in vertical direction is equal to:
  A)
   fluid density                  done clear
  B)
   fluid specific weight done clear
  C)
   fluid weight                   done clear
  D)
   fluid specific gravity done clear
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• question_answer29)
  A piezometer tube is used for the purpose of measurement of:
  A)
   Low pressure                 done clear
  B)
   High pressure done clear
  C)
   Moderate pressure          done clear
  D)
   Vacuum pressure done clear
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• question_answer30)
  The volumetric change of the fluid caused by a resistance is known as:
  A)
   volumetric strain            done clear
  B)
   volumetric index done clear
  C)
   compressibility   done clear
  D)
   stress done clear
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• question_answer31)
  The desirable properties for any practical fluids are:
  A)
   should be viscous done clear
  B)
   should posses surface tension done clear
  C)
   should be compressible done clear
  D)
   All of the above done clear
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• question_answer32)
  Resultant force on a floating body will act:
  A)
   vertically upwards through meta centre done clear
  B)
   vertically down wards through metal centre done clear
  C)
   vertically upwards through centre of buoyancy done clear
  D)
   vertically downwards through centre of buoyancy done clear
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• question_answer33)
  The centre of pressure of a plane submerged surface :
  A)
   should coincide with centroid of surface done clear
  B)
   should coincide with centroid of pressure prism done clear
  C)
   may be above or below centroid done clear
  D)
   cannot be above mentioned done clear
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• question_answer34)
  In a turbulent flow through a pipe, the shear stress is :
  A)
   Maximum at centre and decreased linearly towards the wall done clear
  B)
   Maximum at centre and decreased logarithmically towards the wall done clear
  C)
   Maximum midway between the centre ? line and the wall                       done clear
  D)
   Maximum at the wall and decreases linearly to zero at the centre done clear
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• question_answer35)
  The shear stress in a turbulent pipe flow:
  A)
   varies parabolic ally with radius done clear
  B)
   is constant over the pipe radius done clear
  C)
   is zero at centre and increases linearly to the wall done clear
  D)
   None of these done clear
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• question_answer36)
  The concept of stream function which is based on the principle of continuity is applicable to:
  A)
   Three ? dimensional flow done clear
  B)
   Two ? dimensional flow done clear
  C)
   One ? dimensional flow done clear
  D)
   None of these done clear
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• question_answer37)
  The most essential feature of the turbulent flow is:
  A)
   Large discharge done clear
  B)
   Small discharge done clear
  C)
   High velocity done clear
  D)
   Velocity and pressure at a point shows irregular fluctuations at high frequency done clear
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• question_answer38)
  Ratio of inertia force to surface tension is termed as:
  A)
   Mach number    done clear
  B)
   Froude number done clear
  C)
   Reynolds?s Number        done clear
  D)
   Weber's number done clear
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• question_answer39)
  It \[\frac{P}{\rho g}+\frac{{{v}^{2}}}{2g}+z=\]constant is a Bernoulli's equation, with their usual meanings then the term \[\frac{{{v}^{2}}}{2g}\]represents:
  A)
   kinetic energy             done clear
  B)
   Pressure energy done clear
  C)
   kinetic energy/unit weight done clear
  D)
   None of these done clear
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• question_answer40)
  A pivot tube is used for measuring:
  A)
   pressure of flow  done clear
  B)
   velocity of flow done clear
  C)
   flow rate                       done clear
  D)
   total energy done clear
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• question_answer41)
  Venturimeter is used to measure flow of fluids in pipes when pipe is;
  A)
   horizontal done clear
  B)
   vertical, flow downwards done clear
  C)
   vertical, flow upwards done clear
  D)
   In any position done clear
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• question_answer42)
  Which of the following device is used to measure flow on the application of Bernoulli's theorem:
  A)
   venturimeter                  done clear
  B)
   orifice plate done clear
  C)
   Pivot tude                     done clear
  D)
   All of these done clear
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• question_answer43)
  Flow through a supersonic nozzle is an example of:
  A)
   Isolated system  done clear
  B)
   open system done clear
  C)
   closed system                done clear
  D)
   insulated system done clear
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• question_answer44)
  In the Navier, stoke equation, the forces considered are:
  A)
   Gravity, pressure and viscous done clear
  B)
   Pressure, viscous and turbulence done clear
  C)
   Gravity, pressure, and turbulence done clear
  D)
   Pressure, gravity, turbulence and viscous done clear
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• question_answer45)
  Energy loss in flow through nozzle as compared to ventun meter is:
  A)
   Same   done clear
  B)
   More done clear
  C)
   Less                             done clear
  D)
   Unpredictable done clear
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• question_answer46)
  Which of the following parameter is measured using orifices?
  A)
   Velocity                        done clear
  B)
   Pressure done clear
  C)
   Flow rate          done clear
  D)
   Both pressure and velocity done clear
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• question_answer47)
  The surge tanks are used in a pipeline to:
  A)
   reduce frictional loss in pipe done clear
  B)
   ensure uniform flow in pipe done clear
  C)
   relieve the pressure due to water hammer done clear
  D)
   reduce cavitation done clear
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• question_answer48)
  An impulse turbine is used for:
  A)
   Low head of water         done clear
  B)
   High head of water done clear
  C)
   Medium head of water done clear
  D)
   High discharge done clear
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• question_answer49)
  The function of hydraulic turbine is to convert water energy into:
  A)
   Heat energy                  done clear
  B)
   Electrical energy done clear
  C)
   Atomic energy   done clear
  D)
   Mechanical energy done clear
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• question_answer50)
  The degree of reaction of a kaplan turbine is :
  A)
   equal to 1 done clear
  B)
   equal to 180 done clear
  C)
   Greater than zero but less than 1 11 done clear
  D)
   Greater than 1/2 but less than 1 done clear
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