Hydraulics And Fluid Mechanics Set 3 MCQs

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