### Hydraulics And Fluid Mechanics Set 3

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
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
• 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
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
• 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