Free Solved objective Questions on Fluid Mechanics

1. A fluid is a substance that

(a) Always expands until it fills any container

(b) Has the same shear stress at a point

regardless of its motion

(c) Cannot remain at rest under action of any

shear force

(d) Cannot be subjected to shear forces

ANSWER: (b)

2. Length of mercury column at a place at an

altitude will vary with respect to that at ground

in a

(a) Linear relation

(b) hyperbolic relation

(c) Parabolic relation.

(d) Manner first slowly and then steeply

ANSWER: (d)

3. When power is transmitted through a considerable distance by means of water under

pressure, the maximum power is transmitted when frictional loss of head is

(a) One third of the total head supplied

(b) Half of the total head supplied

(c) 10% of the total head

(d) 17.7% 0f the total head.

ANSWER: (a)

4. A rotameter is a device used to measure

(a) Velocity of fluid in pipes

(b) Velocity of gauges

(c) Votex flow

(d) Flow of fluids

ANSWER: (d)

5. The continuity equation

(a) Expresses relationship between hydraulic

parameters of flow

(b) Expresses the relationship, between work and

energy

(c) Is based on Bernoulli’s theorem

(d) Relates the mass rate of flow along a stream

line.

ANSWER: (d)

6. Of the following, dimensionless parameter is

(a) Pressure coefficient

(b) Froude number

(c) Darcy Weisbach friction factor

(d) All of the above

ANSWER: (d)

7. One dimensional flow

(a) Restricted to flow in a straight line

(b) Neglects changes in a transverse direction

(c) Steady uniform flow

(d) A uniform flow

ANSWER: (b)

8. Steady flow occurs when

(a) Pressure does not change along the flow

(b) Velocity does not change

(c) Conditions change gradually with time

(d) Conditions do not change with time at any point.

ANSWER: (d)

9. Equation Continuity of fluids is applicable only when the flow is

(a) Steady

(b) One dimensional

(c) Compressive

(d) All of the above

ANSWER: (d)

10. If the particles of a fluid attain such velocities that vary from point to point in magnitude and

direction as well as from instant, the flow is

(a) Uniform flow

(b) Steady flow

(c) Turbulent flow

(d) Laminer flow

ANSWER: (c)

11. In a turbulent flow in a pipe

(a) Reynolds number is greater than 10000

(b) Fluid particles move in straight lines

(c) Head loss varies linearly with flow rate

(d) Shear stress varies linearly with radius

ANSWER: (d)

12. In laminar flow, maximum velocity at the centre

Of pipe is how many times to the average velocity

(a) Two

(b) Three

(c) Four

(d) None of the above

ANSWER: (a)

13. A sharp edged obstruction over which the flow

of a fluid takes place is

(a) Wear

(b) Notch

(c) Orifice

(d) None of these

ANSWER: (c)

14. The non-dimensional factor governing frictional resistance is

(a) Reynolds number

(b) Weber number

(c) Froude number

(d) Mach number

ANSWER: (d)

15. Non uniform flow occurs when

(a) Direction and magnitude of velocity at all

points are identical

(b) Velocity of successive fluid particles, at any

point, is same at successive periods of time

(c) Magnitude and direction of velocity do not

change from point to point in the fluid

(d) Velocity, depth, pressure, etc. changes point

to point in the fluid flow

ANSWER: (d)

16. For measuring flow by a venturimeter, it should

be installed in

(a) Vertical line

(b) Horizontal line

(c) Inclined line with upward flow

(d) In any direction and in any location

ANSWER: (d)

17. The fluid forces considered in the Navier Stokes

equation are

(a) Gravity, pressure and viscous

(b) Gravity, pressure and turbulent

(c) Pressure, viscous and turbulent

(d) Gravity, viscous and turbulent

ANSWER: (a)

18. Reynolds number is significant in

(a) Supersonics, as with projectile and jet propulsion

(b) Full immersion or completely enclosed flow,as with pipes, aircraft wings, nozzles etc.

(c) Simultaneous motion through two fluids where there is a surface of discontinuity,

gravity forces, and wave making effect, as with ship’s hulls

(d) All of the above

ANSWER: (b)

Q.51. A streamline is defined as the line

(a) Parallel to central axis flow

(b) Parallel to outer surface to pipe g

(c) Of equal velocity in a flow

(d) Along which the pressure drop is uniform

ANSWER: (c)

19. The cepoletti weir functions as if it were a

following notch without end contractions

(a) Triangular notch

(b) Trapezoidal notch

(c) Rectangular notch

(d) Parallelogram notch

ANSWER: (c)

20.Match number is significant in

(a) Supersonics, as with projectiles and jet

propulsion

(b) Full immersion or completely enclosed flow,

as with pipes, aircrafts wings, nozzles etc.

(c) Simultaneous motion through two fluids

where there is a surface of discontinuity

gravity force, and wave making effects, as

with ship’s hull

(d) All of the above

ANSWER: (a)

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