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This set of Hydraulics and Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on Hydraulics And Fluid Mechanics Set 3

Q1 | A piece of metal of specific gravity 7 floats in mercury of specific gravity 13.6. What fraction of its volume is under mercury?

- 0.5
- 0.4
- 0.515
- 0.5

Q2 | A flow through an expanding tube at constant rate is called

- Steady uniform flow
- Steady non-uniform flow
- Unsteady uniform flow
- Unsteady non-uniform flow

Q3 | Reynolds number is significant in

- Supersonics, as with projectile 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 forces, and wave making effect, as with ship's hulls
- All of the above

Q4 | The loss of head due to friction in a pipe of uniform diameter in which a viscous flow is taking place, is (where RN = Reynold number)

- 1/RN
- 4/RN
- 16/RN
- 64/RN

Q5 | The tendency of a liquid surface to contract is due to the following property

- Cohesion
- Adhesion
- Viscosity
- Surface tension

Q6 | The Newton's law of resistance is based on the assumption that the

- Planes of the body are completely smooth
- Space around the body is completely filled with the fluid
- Fluid particles do not exert any influence on one another
- All of the above

Q7 | For manometer, a better liquid combination is one having

- Higher surface tension
- Lower surface tension
- Surface tension is no criterion
- High density and viscosity

Q8 | The flow in a pipe is neither laminar nor turbulent when Reynold number is

- Less than 2000
- Between 2000 and 2800
- More than 2800
- None of these

Q9 | The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as

- Meta center
- Center of pressure
- Center of buoyancy
- Center of gravity

Q10 | Stoke is the unit of

- Kinematic viscosity in C. G. S. units
- Kinematic viscosity in M. K. S. units
- Dynamic viscosity in M. K. S. units
- Dynamic viscosity in S. I. units

Q11 | The vapour pressure over the concave surface is

- Less man the vapour pressure over the plane surface
- Equal to the vapour pressure over the plane surface
- Greater than the vapour pressure over the plane surface
- Zero

Q12 | The velocity at which the flow changes from laminar flow to turbulent flow is called

- Critical velocity
- Velocity of approach
- Sub-sonic velocity
- Super-sonic velocity

Q13 | Mercury is often used in barometer because

- It is the best liquid
- The height of barometer will be less
- Its vapour pressure is so low that it may be neglected
- Both (B) and (C)

Q14 | A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. Which of the following statement is correct?

- The pressure on the wall at the liquid level is minimum
- The pressure on the bottom of the wall is maximum
- The pressure on the wall at the liquid level is zero, and on the bottom of the wall is maximum
- The pressure on the bottom of the wall is zero

Q15 | Center of pressure compared to e.g. is

- Above it
- Below it
- At same point
- Above or below depending on area of body

Q16 | The centre of gravity of the volume of the liquid displaced by an immersed body is called

- Centre of gravity
- Centre of pressure
- Metacentre
- Centre of buoyancy

Q17 | Gradually varied flow is

- Steady uniform
- Non-steady non-uniform
- Non-steady uniform
- Steady non- uniform

Q18 | The viscosity of water at 20°C is

- One stoke
- One centistoke
- One poise
- One centipoise

Q19 | The velocity of jet of water travelling out of opening in a tank filled with water is proportional to

- Head of water (h)
- h²
- V/T
- h/2

Q20 | According to Darcy's formula, the loss of head due to friction in the pipe is (where f = Darcy's coefficient, l =Length of pipe, v = Velocity of liquid in pipe, and d = Diameter of pipe)

- flv²/2gd
- flv²/gd
- 3flv²/2gd
- 4flv²/2gd

Q21 | According to Bernoulli's equation for steady ideal fluid flow

- Principle of conservation of mass holds
- Velocity and pressure are inversely proportional
- Total energy is constant throughout
- The energy is constant along a streamline but may vary across streamlines

Q22 | The discharge through a convergent mouthpiece is __________ the discharge through an internal mouthpiece of the same diameter and head of water.

- Equal to
- One-half
- Three fourth
- Double

Q23 | Bernoulli equation deals with the law of conservation of

- Mass
- Momentum
- Energy
- Work

Q24 | Principle of similitude forms the basis of

- Comparing two identical equipments
- Designing models so that the result can be converted to prototypes
- Comparing similarity between design and actual equipment
- Hydraulic designs

Q25 | The rise of liquid along the walls of a revolving cylinder about the initial level is __________ the depression of the liquid at the axis of rotation.

- Same as
- Less than
- More than
- None of these