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This set of Hydraulics and Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on Hydraulics And Fluid Mechanics Set 1

Q1 | When a body is placed over a liquid, it will sink down if

- Gravitational force is equal to the up-thrust of the liquid
- Gravitational force is less than the up-thrust of the liquid
- Gravitational force is more than the up-thrust of the liquid
- None of the above

Q2 | The property by virtue of which a liquid opposes relative motion between its different layers iscalled

- Surface tension
- Coefficient of viscosity
- Viscosity
- Osmosis

Q3 | A weir is said to be narrow-crested weir, if the width of the crest of the weir is __________ halfthe height of water above the weir crest.

- Equal to
- Less than
- More than
- None of these

Q4 | Euler's dimensionless number relates the following

- Inertial force and gravity
- Viscous force and inertial force
- Viscous force and buoyancy force
- Pressure force and inertial force

Q5 | When a body floating in a liquid, is displaced slightly, it oscillates about

- C.G. of body
- Center of pressure
- Center of buoyancy
- Metacentre

Q6 | When the Mach number is between __________ the flow is called super-sonic flow.

- 1 and 2.5
- 2.5 and 4
- 4 and 6
- 1 and 6

Q7 | In an immersed body, centre of pressure is

- At the centre of gravity
- Above the centre of gravity
- Below be centre of gravity
- Could be above or below e.g. depending on density of body and liquid

Q8 | Steady flow occurs when

- The direction and magnitude of the velocity at all points are identical
- The velocity of successive fluid particles, at any point, is the same at successive periods of time
- The magnitude and direction of the velocity do not change from point to point in the fluid
- The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

Q9 | A flow is called super-sonic if the

- Velocity of flow is very high
- Discharge is difficult to measure
- Mach number is between 1 and 6
- None of these

Q10 | In a forced vortex, the velocity of flow everywhere within the fluid is

- Maximum
- Minimum
- Zero
- Nonzero finite

Q11 | Mach number is significant in

- Supersonics, as with projectiles and jet propulsion
- Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
- Simultaneous motion through two fluids where there is a surface of discontinuity, gravity force, and wave making effects, as with ship's hulls
- All of the above

Q12 | In order that flow takes place between two points in a pipeline, the differential pressure betweenthese points must be more than

- Frictional force
- Viscosity
- Surface friction
- All of the above

Q13 | The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a triangular notch is given by

- dQ/Q = 3/2 × (dH/H)
- dQ/Q = 2 × (dH/H)
- dQ/Q = 5/2 × (dH/H)
- dQ/Q = 3 × (dH/H)

Q14 | For similarity, in addition to models being geometrically similar to prototype, the following in both cases should also be equal

- Ratio of inertial force to force due to viscosity
- Ratio of inertial force to force due to gravitation
- Ratio of inertial force to force due to surface tension
- All the four ratios of inertial force to force due to viscosity, gravitation, surface tension, and elasticity

Q15 | The value of coefficient of velocity for a sharp edged orifice __________ with the head of water.

- Decreases
- Increases
- Remain same
- None of these

Q16 | If cohesion between molecules of a fluid is greater than adhesion between fluid and glass, then the free level of fluid in a dipped glass tube will be

- Higher than the surface of liquid
- The same as the surface of liquid
- Lower than the surface of liquid
- Unpredictable

Q17 | The ratio of the inertia force to the __________ is called Euler's number.

- Pressure force
- Elastic force
- Surface tension force
- Viscous force

Q18 | A one dimensional flow is one which

- Is uniform flow
- Is steady uniform flow
- Takes place in straight lines
- Involves zero transverse component of flow

Q19 | According to Manning's formula, the discharge through an open channel is (where M = Manning's constant)

- A × M × m1/2 × i2/3
- A × M × m2/3 × i1/2
- A1/2 × M 2/3 × m × i
- A2/3 × M1/3 × m × i

Q20 | An opening in the side of a tank or vessel such that the liquid surface with the tank is below the top edge of the opening, is called

- Weir
- Notch
- Orifice
- None of these

Q21 | The property of fluid by virtue of which it offers resistance to shear is called

- Surface tension
- Adhesion
- Cohesion
- Viscosity

Q22 | Coefficient of velocity is defined as the ratio of

- Actual velocity of jet at vena contracta to the theoretical velocity
- Area of jet at vena contracta to the area of orifice
- Actual discharge through an orifice to the theoretical discharge
- None of the above

Q23 | The mass of 2.5 m3 of a certain liquid is 2 tonnes. Its mass density is

- 200 kg/m3
- 400 kg/m3
- 600 kg/m3
- 800 kg/m3

Q24 | A fluid in equilibrium can't sustain

- Tensile stress
- Compressive stress
- Shear stress
- Bending stress

Q25 | When a plate is immersed in a liquid parallel to the flow, it will be subjected to a pressure __________ that if the same plate is immersed perpendicular to the flow.

- Less than
- More than
- Equal to
- None of these