Fluid Mechanics - MCQ PDF

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Seat No Total number of questions : 60 1000782_T1 FLUID MECHANICS COURSE 2015 Time : 1hr Max Marks : 50 N.B 1) All questions are Multiple Choice Questions having single correct option. 2) Attempt any 50 questions out of 60. 3) Use of calculator is allowed. 4) Each question carries 1 Mark. 5) Specially abled students are allowed 20 minutes extra for examination. 6) Do not use pencils to darken answer. 7) Use only black/blue ball point pen to darken the appropriate circle. 8) No change will be allowed once the answer is marked on OMR Sheet. 9) Rough work shall not be done on OMR sheet or on question paper. 10) Darken ONLY ONE CIRCLE for each answer.

Q.no 1. The flow of an oil through small diameter (not more than a mm) tube is likely to be A : Laminar B : Turbulent C : Transitional and Turbulent D : Transitional Q.no 2. The force per unit length is the unit of A : surface tension B : compressibility C : capillarity D : viscosity

Q.no 3. Which of the following is a case of turbulent flow? A : flow of oil in measuring instruments B : flow of sap in trees C : flow of water through pipe D : flow of blood in arteries Q.no 4. A pathline describes A : the velocity direction at all points on the line B : the path followed by particles in a flow C : the path over a period of times of a single particle that has passed out at a point D : the instantaneous position of all particles that have passed a point Q.no 5. A fluid having no viscosity is known as A : real fluid B : ideal fluid C : Newtonian fluid D : non-Newtonian fluid Q.no 6. The observer concentration on a fixed point in the fluid system occurs in which method A : Lagrangian method B : Eularian method C : Both (a) and (b) D : None of the above Q.no 7. The force due to weight of the fluid A : Pressure B : Viscous C : Surface tension D : None of the above

Q.no 8. Surface tension is a phenomenon due to A : cohesion only B : viscous force C : adhesion between liquid & solid molecules D : difference in magnitude between the forces due to adhesion & cohesion Q.no 9. A flow is characterized as laminar, transitional or turbulent based on A : Weber number B : Froude number C : Reynolds number D : Mach number Q.no 10. The length of the divergent cone in a venturimeter is __________ that of the convergent cone. A : equal to B : double C : three to four times D : five to six times Q.no 11. The ratio of inertia force to viscous force is known as A : Mach number B : Reynolds number C : Froude number D : Weber number Q.no 12. Local atmospheric pressure is measured by A : a mercury barometer B : A Bourdon gauge C : A vacuum gauge D : A manometer

Q.no 13. The point at which the resultant pressure on an immersed surface acts, is known as A : centre of gravity B : centre of depth C : centre of pressure D : centre of immersed surface Q.no 14. The term Z in Bernoulli equation, is known as A : potential energy B : pressure energy C : potential energy per unit weight D : none of the above Q.no 15. Non uniform flow occurs when A : the velocity, depth, pressure, etc. change from point to point in the fluid flow B : the velocity of successive fluid particles, at any point, is the same at successive periods of time C : the magnitude and direction of the velocity do not change from point to point in the fluid D : the fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane Q.no 16. Laminar flow generally occurs for cases involving A :  very slow motions B :  very viscous fluids C : very narrow passages or capillary tubes D :  all of the above Q.no 17. For pipes, laminar flow occurs when Reynolds number is A : less than 2000 B : between 2000 and 4000

C : more than 4000 D : less than 4000 Q.no 18. The weight per unit volume of a liquid at a standard temperature and pressure is called A : specific weight B : mass density C : specific gravity D : none of these Q.no 19. Vapour pressure of a liquid is due do A : the pressure of flow B : the molecules of liquid which hang over the free-surface C : the pressure of air above the free surface D : the existence of free surface Q.no 20. When a body, floating in a liquid, is given a small angular displacement, it starts oscillating about a point known as A : centre of pressure B : centre of gravity C : centre of buoyancy D : metacentre Q.no 21. If the Reynolds number is less than 2000, the flow in a pipe is A : Laminar B : Turbulent C : Translational D : Mixed Q.no 22. The inlet length of a venturimeter A : is equal to the outlet length

B : is more than the outlet length C : is less than the outlet length D : none of the above Q.no 23. The flow of fluid in the pipe is laminar only when A : Reynolds no. is more than 2000 B : Reynolds no. is less than 2000 C : Reynolds no. is in between 2000 to 4000 D : Reynolds no. is more than 4000 Q.no 24. Laminar flow generally occurs for cases involving A : low viscous fluid B : very broad passages C : very high motion D : none of these Q.no 25. In a Poiseuille flow, the acceleration of a fluid particle is A : zero B : increases with time C : increases with length D : none of these Q.no 26. During the flow, if volume and hence density changes, due to change in pressure and temperature, the flow is A : irrotational B : rotational C : compressible D : incompressible Q.no 27. The piezometric head is the summation of A : velocity head and pressure head

B : pressure head and elevation head C : velocity head and elevation head D : none of the above Q.no 28. The friction factor 'f' for laminar flow in pipe is found to be 0.032.The Reynolds no. in the flow is A : 1000 B : 2000 C : 2500 D : 1600 Q.no 29. A stagnation point is a point : A : where the pressure is zero B : where the total energy is zero C : where the velocity of flow reduces to zero D : where the total energy is maximum Q.no 30. For venturimeter flow always takes place from A : Converging cone to diverging cone B : Diverging cone to converging cone C : Both (a) & (b) D : None of these Q.no 31. The pressure drop per unit length of a pipe for laminar flow is A : = (12฀VavgL)/฀gD2 B : = (32฀VavgL)/฀gD2 C : = (12฀Vavg)/฀gD2 D : none of these Q.no 32. The pressure in 'Pascal’ s at a depth of 1m below the free surface of a body of water will be equal to…

A : 1 Pa B : 98.1 Pa C : 981 Pa D : 9810 Pa Q.no 33. One stoke is equal to A : 1 cm²/s B : 1m²/s C : 1 ft²/s D : 1 mm²/s Q.no 34. Uniform flow occurs when A : the flow is steady B : the flow is streamline C : size and shape of the cross section in a particular length remain constant D : size and cross section change uniformly along length Q.no 35. The stream function is A : constant along an equipotential line B : constant along a streamline C : defined only in irrotational flow D : defined only for incompressible flow Q.no 36. The sheet of liquid escaping over the notch is called A : nappe B : crest C : crest height D : head over the notch Q.no 37. In a fully developed, steady, incompressible, laminar flow through a pipe

A : the pressure gradient along the flow is zero B : the pressure gradient along the flow varies linearly C : the pressure gradient along the flow is constant D : None of the above Q.no 38. The Redwood viscometer used for measurement of viscosity are based on A : Stokes law B : Chezy’s equation C : Hagen-Poiseulle equation D : Darcy-Weisbach equation Q.no 39. Cavitation in fluid flow occurs when : A : The total energy suddenly increases B : Total energy decreases suddenly C : The pressure of flow decreases to a value close to its vapour pressure D : The velocity head reduces to zero Q.no 40. The component of acceleration due to nonuniformity of flow is called A : normal acceleration B : tangential acceleration C : convective acceleration D : local acceleration Q.no 41. The total energy line is always higher than the hydraulic gradient line, the vertical distance between the two representing: A : The pressure head B : The piezometric head C : The velocity head D : None of the above

Q.no 42. The flow in which the particles of a fluid attain such velocities that vary from point to point in magnitude and direction as well as from instant to instant, is known as A : one dimensional flow B : uniform flow C : steady flow D : turbulent flow Q.no 43. For the laminar flow between two parallel plates A : the maximum velocity = 2.0 times the average velocity B : the maximum velocity = 1.35 times the average velocity C : the maximum velocity = 1.5 times the average velocity D : None of these Q.no 44. The shear stress at a point 4 cm from the pipe axis is 20 Pa. The shear stress at a pipe wall of 20 cm diameter will be A : 50 Pa B : 27.5 Pa C : 8 Pa D : Insufficient data Q.no 45. Mercury is often used in barometer because A : it is the best liquid B : the height of barometer will be less C : its vapourpressure is so low that it may be neglected D : both(b)and(c) Q.no 46. Which of the following is an incorrect statement ? A : Coefficient of contraction of a venturimeter is almost unity. B : Flow nozzle is cheaper than venturimeter but has higher energy loss.

C : Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined. D : None of the above statement is correct. Q.no 47. In laminar flow between two fixed parallel plates the ratio of avg velocity to that of max. velocity is A : 3/2 B : 4/5 C : 5/4 D : 2/3 Q.no 48. The velocity distribution in Poiseuille flow follow the A : Parabolic law B : Cubic law C : Linear law D : Logarithmic law Q.no 49. Which of the following is/are examples of Laminar flow? A : Underground flow B : Flow past tiny bodies C : Flow of oil measuring instruments D : all of the above Q.no 50. The flow in which each liquid particle has a definite path and their paths do not cross each other is called A : one dimensional flow B : streamline flow C : steady flow D : turbulent flow Q.no 51. Calculate the loss of head in the pipe having diameter of 15 cm and the length of 2 km. It carries laminar flow of oil of specific gravity 0.85 and viscosity of 6 stokes at the rate of 30.48 l.p.s.

A : 100 B : 200 C : 300 D : 400 Q.no 52. A horizontal pipe is gradually enlarged from A to B .The velocity at A is 8 m/s and diameter is 0.5 m.If velocity at B is 2 m/s, the diameter at B will be A : 0.25 m B : 0.5 m C : 1.75 m D:1m Q.no 53. An oil of kinematic viscosity 0.25 stokes flows through a pipe of 10 cm diameter. The flow is critical at a velocity about A : 0.5 m/s B : 1.5 m/s C : 7.2 m/s D : 0.72 m/s Q.no 54. Two parallel plates kept 80 mm apart have laminar flow of oil between them. The max. velocity of flow is 2 m/s then calculate discharge per meter width. (in cubic meter per sec) A : 0.1067 B : 089 C : 1.11 D : 0.15 Q.no 55. With an increase in size of tube, the rise or depression of liquid in the tube due to tension will A : Decrease B : Increase C : remain unchanged

D : depend upon the characteristics of liquid Q.no 56. Pick up the correct statements of the following : 1.potential function is defined for irrotational flows only 2.stream function is defined for two dimensional flows only 3.in steady flow total acceleration is zero. A : all are correct B : 2 and 3 C : 1 and 2 D : 1 and 3 Q.no 57. A venturimeter of size 200 mm x 100 mm is used to measure the flow of liquid of sp. Gr. 0.85 if the mercury differential manometer head is 250 mm. if the pressure of the inlet is 49 kPa then the absolute pressure at the throat is A : 90.45 kPa B : 125.65 kPa C : 119.05 kPa D : 80.30 kPa Q.no 58. Diameters of a tapering pipe at section 1-1 and 2-2 are 100 mm and 150 mm respectively. If velocity of water flowing through the pipe at section 1-1 is 5 m/s. Find Velocity of water at section 2-2 of the pipe A : 2.5 m/s B : 2.22 m/s C : 3.1 m/s D : 2 m/s Q.no 59. An orifice is discharging under a head of 1.25m of water. A pitot tube kept at its centre line at the vena-contracta indicates a head of 1.20m of the water. The coefficient of velocity of the surface is A : 0.99 B : 0.98 C : 0.965 D : 0.96

Q.no 60. "Flow at constant rate through a tapering pipe is i) steady flow ii) uniform flow iii) unsteady flow iv) non-uniform flow The correct answer is" A : (i) and (ii) B : (i)and(iv) C : (ii) and (iii) D : (ii) and (iv) Q.no 1. A notch is used to measure __________ of liquids. A : Pressure B : Discharge C : Velocity D : volume Q.no 2. In a fully developed, steady, incompressible laminar flow through a pipe, the flow velocity at the wall is A : Maximum B : Zero C : Constant D : Equal to velocity gradient Q.no 3. Bernoulli's equation is applied to A : Venturimeter B : Orificemeter C : Pitot tube D : All of these Q.no 4. A pitot tube is used to measure the A : velocity of flow at the required point in a pipe

B : pressure difference between two points in a pipe C : total pressure of liquid flowing in a pipe D : discharge through a pipe. Q.no 5. Maximum velocity of one dimensional incompressible fully developed viscous flow, between two fixed parallel plates is 6 m/s. The mean velocity in m/s of flow is A:2 B:3 C:4 D:5 Q.no 6. Standard atmospheric pressure in terms of water column is A : 9.81 m B : 10.33 m C : 8.75 m D : 12.35 m Q.no 7. The shear stress-strain graph for a Newtonian fluid is a A : straight line B : parabolic curve C : hyperbolic curve D : Elliptical Q.no 8. The actual path traced by a fluid particle over a period 0f time is called as A : path line B :  streamline C : streak line D : stream tube Q.no 9. Uniform flow occurs when

A : the direction and magnitude of the velocity at all points are identical B :  the velocity of successive fluid particles, at any point, is the same at successive periods of time C : the magnitude and direction of the velocity do not change from point to point in the fluid D : the fluid particles move in plane or parallel planes and the streamline patterns are identical in each planes Q.no 10. The path traced by a particles of smoke issuing from a cigarette is a A : streamline B : pathline C : laminar flow D : streak line Q.no 11. When the fluid flows through a pipe line under viscous flow condition, the ratio of velocity at the axis of pipe to the mean velocity of flow is A : 0.5 B : 0.707 C : 1.67 D:2 Q.no 12. The buoyancy depends upon the A : weight of the liquid displaced B : pressure with which the liquid is displaced C : viscosity of the liquid D : compressibility of the liquid Q.no 13. The laminar flow is characterized by A : existence of eddies B : movement of fluid particles is irregular C : Reynolds no. is less than critical value

D : Reynolds no. is high for flow Q.no 14. In a fully developed, steady, incompressible laminar flow through a pipe, the shear stress at the centreline is A : zero B : Maximum C : Equal to average velocity D : None of these Q.no 15. Bernoulli’s equation is obtained from A : Reynold’s Equation B : Euler’s Equation C : Navier-Stokes Equation D : All of these Q.no 16. Flow occurring in a pipeline when a valve is being opened is A : steady B : unsteady C : laminar D : vortex Q.no 17. Which of the following is the wrong statement in the context of laminar flow through a pipeline? A : shear stress is zero at the centre and varies linearly with pipe radius B : head loss is proportional to cube of average flow velocity C : the friction factor varies inversely with flow Reynolds number D : no dispersion of dye injected into the flow stream Q.no 18. The ratio of the area of the jet of water at vena-contracta to the area of orifice, is known as A : co-efficient of discharge B : co-efficient of velocity

C : co-efficient of contraction D : co-efficient of viscosity Q.no 19. The force present in a moving liquid is/are A : Inertia force B : Viscous Force C : Gravity force D : All of these Q.no 20. In case of laminar flow the loss of pressure head is proportional A : to velocity B : to square of velocity C : to velocity cube D : none of these Q.no 21. Coefficient of velocity is defined as the ratio of A : actual velocity of jet at vena contracta to the theoretical velocity B : area of jet at vena contracta to the area of orifice C : actual discharge through an orifice to the theoretical discharge D : None of these Q.no 22. The flow which neglects changes in a transverse direction is known as A : one dimensional flow B : uniform flow C : steady flow D : turbulent flow Q.no 23. A one dimensional flow is one which A : is uniform flow B : is steady uniform flow

C : takes place in straight lines D : involves zero transverse component of flow Q.no 24. A point, in a compressible flow where the velocity of fluid is zero, is called A : critical point B : vena contracta C : stagnation point D : none of these Q.no 25. A Venturimeter is a device based on the Bernoulli principle & is used for measuring : A : Piezometric head B : Velocity head C : flowrate D : total energy Q.no 26. For 3-dimensional flow, the velocity distribution is A : parabolic B : straight line C : hyperbolic D : logarithmic Q.no 27. The mass of 2.5 m3 of a certain liquid is 2 tonnes. Its mass density is A : 200 kg/m3 B : 400 kg/m3 C : 600 kg/m3 D : 800 kg/m3 Q.no 28. A floating body will remain in stable equilibrium so long as : A : the metacentre M lies below the centre of gravity G

B : the metacentre M lies above the centre of gravity G C : the metacentre & the centre of gravity remains at the same position. D : none of the above Q.no 29. The pressure at the bottom of a tank containing a liquid doesnot depend on,… A : Acceleration due to gravity B : Area of the bottom surface C : Height of the liquid column D : Nature of the liquid. Q.no 30. In a steady, fully developed laminar flow in a pipe, the acceleration of a fluid particle is A : equal to zero B : increases with time C : increases with length D : none of these Q.no 31. The Bernoulli's equation written in the conventional form V²/2g+ p/w +z =constant; represents total energy per unit of certain quantity. Identify this quantity from the choice given below : A : energy per unit volume B : energy per unit mass C : energy per unit weight D : energy per unit specific weight Q.no 32. When a body is placed over a liquid, it will float if A : gravitational force is equal to the upthrust of the liquid B : gravitational force is less than the upthrust of the liquid C : gravitational force is more than the upthrust of the liquid D : none of the above

Q.no 33. The criterion for stability of a floating body depends on : A : the relative position of centre of buoyancy & the centre of gravity B : The relative position of the metacentre & the centre of buoyancy C : the relative position of the metacentre & the centre of gravity D : none of the above Q.no 34. In a Poiseuille flow, the flow velocity at the centerline is A : Maximum B : Zero C : Constant D : Equal to velocity gradient Q.no 35. The pressure gradient in a Couette flow A : Varies linearly B : Varies parabolically C : Varies cubically D : zero Q.no 36. The intensity of pressure at any point, in a liquid, is A : directly proportional to the area of the vessel containing liquid B : directly proportional to the depth of liquid from the surface C : directly proportional to the length of the vessel containing liquid D : inversely proportional to the depth of liquid from the surface Q.no 37. The term V²/2g in Bernoulli equation, is known as A : kinetic energy B : pressure energy C : kinetic energy per unit weight D : none of the above

Q.no 38. In a fully developed, steady, incompressible laminar flow through a pipe, the shear stress at the wall is A : zero B : Maximum C : Equal to average velocity D : None of these Q.no 39. The total pressure on a horizontally immersed surface is (where w = Specific weight of the liquid, A = Area of the immersed surface, and x = Depth of the centre of gravity of the immersed surface from the liquid surface) A : w.A B : wx C : wAx D : wA/x Q.no 40. The flow in which the velocity vector is identical in magnitude and direction at every point, for any given instant, is known as A : one dimensional flow B : uniform flow C : streamline flow D : turbulent flow Q.no 41. Stoke is the unit of A : kinematic viscosity in C. G. S. units B : kinematic viscosity in M. K. S. units C : dynamic viscosity in M. K. S. units D : dynamic viscosity in S. I. units Q.no 42. In case of curved converging stream line pattern, there is A : convective tang...