Fluid Mechanics Quizzes: Test Your Understanding

Question 1

Which of the following is a key characteristic of pressure within a fluid, as described by Pascal's law?

Accepted Answer

It is evenly distributed in all directions.

Answer

It is only significant in the downward direction.

Answer

It is always a positive value.

Answer

It is only relevant in fluids that are stationary.

Question 2

In a pipe with varying cross-sectional area, where will the fluid velocity be the highest?

Accepted Answer

At the point with the smallest cross-sectional area

Answer

At the point with the largest cross-sectional area

Answer

At the point with the highest pressure

Answer

At the point with the highest temperature

Question 3

In laminar flow through a circular pipe, which velocity profile accurately represents the flow behavior?

Accepted Answer

Parabolic velocity profile, with zero velocity at the pipe wall and maximum velocity at the pipe center

Answer

Uniform velocity across the pipe radius

Answer

Linear velocity profile, with velocity increasing linearly from zero at the pipe wall to maximum at the pipe center

Answer

Exponential velocity profile, with velocity decaying exponentially from the pipe center to the pipe wall

Question 4

Viscosity is a fluid property that describes its resistance to flow. Which of the following options best defines viscosity?

Accepted Answer

The internal friction within a fluid that opposes the relative motion of its layers

Answer

The tendency of a fluid to resist changes in volume

Answer

The ability of a fluid to store energy when deformed

Answer

The tendency of a fluid to form droplets

Question 5

A cylindrical pipe with diameter 'd' carries water flowing at velocity 'v'. If the pipe's diameter is halved to 'd/2' while maintaining the same flow rate, what will be the new water velocity?

Accepted Answer

2v

Answer

v

Answer

4v

Answer

8v

Question 6

According to Bernoulli's principle, what happens to fluid pressure when fluid velocity increases?

Accepted Answer

Decreases

Answer

Increases

Answer

Stays the same

Answer

Increases then decreases

Question 7

Which property is **exclusive** to fluids?

Accepted Answer

Fluidity

Answer

Mass

Answer

Volume

Answer

Temperature

Question 8

Which quantity is NOT a fundamental dimension in fluid mechanics?

Accepted Answer

Temperature

Answer

Mass

Answer

Length

Answer

Time

Question 9

What is the SI unit of pressure?

Accepted Answer

Newtons per square meter (N/m^2)

Answer

Meters per second (m/s)

Answer

Kilograms per cubic meter (kg/m^3)

Question 10

Which of the following is NOT a dimensionless parameter in fluid mechanics?

Accepted Answer

Specific gravity

Answer

Reynolds number

Answer

Froude number

Answer

Euler number

Question 11

Which of the following is NOT a fundamental principle or property in fluid mechanics?

Accepted Answer

Volume Flux

Answer

Bernoulli's Principle

Answer

Density

Answer

Viscosity

Question 12

In a pipe carrying an incompressible fluid under steady-state conditions, how does the fluid velocity change as the pipe diameter increases, assuming a constant mass flow rate?

Accepted Answer

Fluid velocity is inversely proportional to the square of the pipe diameter.

Answer

Fluid velocity is directly proportional to the pipe diameter.

Answer

Fluid velocity remains constant regardless of the pipe diameter.

Answer

Fluid velocity is directly proportional to the square of the pipe diameter.

Question 13

In a turbine, which parameter has a significant impact on the energy extracted from the flowing fluid?

Accepted Answer

Turbine Blade Angle

Answer

Fluid Temperature

Answer

Pipe Diameter

Answer

Fluid Viscosity

Question 14

Which of the following statements about the relationship between density and pressure of a fluid is **false**?

Accepted Answer

Density and pressure are directly proportional to each other.

Answer

Density is a measure of the mass per unit volume of a fluid.

Answer

Pressure is a measure of the force per unit area exerted by a fluid.

Answer

Viscosity is a measure of the resistance of a fluid to flow.

Question 15

In laminar flow through a circular pipe, what is the relationship between the average velocity (V_avg) and the maximum velocity (V_max) at the pipe's center?

Accepted Answer

V_avg = 0.5 * V_max

Answer

V_avg = V_max

Answer

V_avg = 2 * V_max

Question 16

In fluid mechanics, which quantity describes both the speed and direction of a fluid particle?

Accepted Answer

Velocity

Answer

Pressure

Answer

Density

Answer

Temperature

Question 17

A fluid is at rest. Which of the following statements about its pressure is accurate?

Accepted Answer

Pressure within a fluid increases proportionally with depth for all fluids, regardless of their compressibility.

Answer

Pressure at a specific depth in the fluid is dependent on the shape of the container holding the fluid.

Answer

Pressure at a particular depth is identical for all types of fluids.

Question 18

Which of the following is NOT a factor influencing the flow regime of a fluid through a pipe?

Accepted Answer

Pipe length

Answer

Fluid velocity

Answer

Pipe diameter

Answer

Fluid viscosity

Question 19

In fluid mechanics, viscosity is a measure of a fluid's resistance to flow. What is the fundamental dimension of viscosity, and how does it impact our understanding of fluid flow behavior?

Accepted Answer

Force per unit area per unit time

Answer

Mass per unit time

Answer

Force per unit length

Question 20

Define the boundary layer in fluid flow. Explain how its thickness is influenced by fluid characteristics and flow conditions.

Accepted Answer

A thin layer near a solid surface where viscous forces dominate, reducing flow velocity compared to the main flow.

Answer

Boundary layer thickness remains constant, unaffected by fluid properties or flow conditions.

Answer

Boundary layers occur only in laminar flows, not in turbulent flows.

Question 21

In a fluid system, a diffuser is primarily designed to:

Accepted Answer

Decrease fluid velocity

Answer

Increase fluid velocity

Answer

Reduce fluid pressure

Answer

Increase fluid temperature

Question 22

In fluid mechanics, which of the following is a measure of the fluid's resistance to flow?

Accepted Answer

Viscosity

Answer

Density

Answer

Pressure

Answer

Surface tension

Question 23

A fluid is said to be at rest when:

Accepted Answer

There are no shear stresses acting on it

Answer

There are no normal stresses acting on it

Answer

The pressure is constant throughout

Answer

Its velocity is constant throughout

Question 24

The Bernoulli equation for incompressible flow relates:

Accepted Answer

Pressure, velocity, and height

Answer

Pressure, volume, and temperature

Answer

Stress, strain, and modulus

Answer

Volume, mass, and density

Question 25

The dimensionless parameter that characterizes fluid flow in pipes is:

Accepted Answer

Reynolds number

Answer

Froude number

Answer

Mach number

Answer

Nusselt number

Question 26

The efficiency of a pump is defined as the ratio of:

Accepted Answer

Power output to power input

Answer

Power input to power output

Answer

Flow rate to head

Answer

Head to flow rate

Question 27

Which of the following is NOT considered a fundamental fluid property?

Accepted Answer

Hardness

Answer

Density

Answer

Viscosity

Answer

Temperature

Question 28

The mass flow rate (Q) through a pipe can be calculated using the equation:

Accepted Answer

Q = A * v

Answer

Q = A * v^2

Answer

Q = 1/2 * A * v

Answer

Q = A * v^3

Question 29

The Reynolds number (Re) is primarily used to predict:

Accepted Answer

Flow regime (laminar or turbulent)

Answer

Pressure drop in a pipe

Answer

Friction factor for a fluid flow

Answer

Heat transfer coefficient

Question 30

The Bernoulli equation is commonly used for:

Accepted Answer

Analyzing fluid flow in pipes

Answer

Calculating lift on an airfoil

Answer

Predicting flow separation

Answer

Determining pressure loss in pumps

Question 31

Which property listed below is NOT a fundamental property of fluids?

Accepted Answer

Electrical conductivity

Answer

Density

Answer

Viscosity

Answer

Temperature

Question 32

The Bernoulli equation can be applied to which type of flow?

Accepted Answer

Both steady and incompressible flow

Answer

Steady flow

Answer

Incompressible flow

Answer

Viscous flow

Question 33

The efficiency of a centrifugal pump is defined as:

Accepted Answer

Ratio of power output to power input

Answer

Ratio of head developed to head applied

Answer

Ratio of flow rate to discharge pressure

Answer

Ratio of torque to speed

Question 34

Which dimensionless number is used to characterize the flow regime in a pipe?

Accepted Answer

Reynolds number

Answer

Froude number

Answer

Weber number

Answer

Mach number

Question 35

The boundary layer in fluid flow is characterized by:

Accepted Answer

High velocity gradients

Answer

Low velocity gradients

Answer

No velocity gradients

Answer

Uniform velocity distribution

Question 36

Cavitation in fluid machinery refers to the phenomenon of:

Accepted Answer

Formation of vapor bubbles

Answer

Increase in pressure

Answer

Decrease in flow rate

Answer

Rise in temperature

Question 37

The pressure at a depth 'h' within a fluid is given by:

Accepted Answer

ρgh

Answer

ρg/h

Answer

gh/ρ

Answer

ρh/g

Question 38

The efficiency of a centrifugal pump is expressed as the ratio of:

Accepted Answer

Work output to power input

Answer

Power input to work output

Answer

Head generated to power input

Answer

Power input to head generated

Question 39

Which of the following is NOT a classification of fluid flow?

Accepted Answer

Compressible

Answer

Laminar

Answer

Turbulent

Answer

Incompressible

Question 40

The Reynolds number is primarily used to determine:

Accepted Answer

The transition from laminar to turbulent flow

Answer

The pressure drop in a pipe

Answer

The efficiency of a pump

Answer

The drag force on a sphere

Question 41

Which of the following is NOT a fundamental property of fluids?

Accepted Answer

Elasticity

Answer

Density

Answer

Viscosity

Answer

Compressibility

Question 42

The pressure at a point in a static fluid is:

Accepted Answer

Proportional to fluid depth

Answer

Independent of fluid depth

Answer

Inversely proportional to fluid depth

Answer

Zero

Question 43

The continuity equation for an incompressible fluid flowing through a pipe states that:

Accepted Answer

Mass flow rate is constant

Answer

Velocity is constant

Answer

Pressure is constant

Answer

Temperature is constant

Question 44

Which type of pump is most suitable for high-head, low-flow applications?

Accepted Answer

Positive displacement

Answer

Centrifugal

Answer

Axial

Answer

Jet

Question 45

The Reynolds number is a dimensionless parameter that characterizes:

Accepted Answer

Flow regime

Answer

Fluid viscosity

Answer

Pipe diameter

Answer

Flow velocity

Question 46

Which of the following is NOT a dimensionless drag coefficient?

Accepted Answer

Reynolds number

Answer

Lift coefficient

Answer

Friction coefficient

Answer

Drag coefficient

Question 47

The cavitation number is a dimensionless parameter that characterizes:

Accepted Answer

Cavitation potential

Answer

Pump efficiency

Answer

Flow regime

Answer

Fluid viscosity

Question 48

In a fluid flowing through a circular pipe, the pressure gradient along the pipe's axis is given by which equation?

Accepted Answer

(a) ΔP = - f * (L/D) * (ρ * V²) / 2

Answer

(b) ΔP = - (μ * V * L) / (ρ * D²)

Answer

(c) ΔP = - (ρ * V * ΔL) / μ

Answer

(d) ΔP = - (12 * μ * V * L) / (ρ * D²)

Question 49

Which type of fluid flow is characterized by irregular and chaotic motion?

Accepted Answer

Turbulent flow

Answer

Laminar flow

Answer

Viscous flow

Answer

Compressible flow

Question 50

Which of the following devices measures the velocity of a fluid?

Accepted Answer

Pitot tube

Answer

Pressure gauge

Answer

Thermocouple

Answer

Flowmeter

Question 51

The Reynolds number is a dimensionless parameter used to predict:

Accepted Answer

Whether a flow is laminar or turbulent

Answer

The compressibility of a fluid

Answer

The surface tension of a fluid

Answer

The viscosity of a fluid

Question 52

Which of the following techniques reduces the drag force on an object moving through a fluid?

Accepted Answer

Streamlining

Answer

Increasing the surface roughness

Answer

Increasing the velocity

Answer

Increasing the fluid density

Question 53

Viscosity in fluids leads to:

Accepted Answer

Shear stresses within the fluid

Answer

Increased flow rates

Answer

Reduced pressure drop

Answer

Enhanced turbulence

Question 54

The pressure coefficient for a pipe represents the ratio of:

Accepted Answer

Pressure drop to velocity squared

Answer

Friction factor to Reynolds number

Answer

Pipe length to pipe diameter

Answer

Flow rate squared to pipe area

Question 55

Which unit is NOT a unit of viscosity?

Accepted Answer

Pascal

Answer

Poiseuille

Answer

Pascal-second

Answer

Centipoise

Question 56

The pressure at a depth 'h' in a fluid of density 'ρ' is:

Accepted Answer

ρgh

Answer

ρgh/2

Answer

ρg/h

Answer

ρh/g

Question 57

Which of the following is NOT a component of the Navier-Stokes equation?

Accepted Answer

Elastic forces

Answer

Inertial forces

Answer

Pressure forces

Answer

Viscous forces

Question 58

A pump that raises water to a height of 10 m at a flow rate of 1 m³/s requires a power of:

Accepted Answer

1962 W

Answer

981 W

Answer

9810 W

Answer

19620 W

Question 59

Viscosity of a fluid can be measured using a:

Accepted Answer

Viscometer

Answer

Manometer

Answer

Anemometer

Answer

Hygrometer

Question 60

The continuity equation describes the conservation of:

Accepted Answer

Mass

Answer

Momentum

Answer

Energy

Answer

Volume

Question 61

In fluid systems, what strategies are commonly used to control and minimize drag? Consider both boundary layer manipulation and the use of additives.

Accepted Answer

Boundary layer manipulation and drag-reducing additives

Answer

Boundary layer manipulation only

Answer

Drag-reducing additives only

Answer

Neither boundary layer manipulation nor drag-reducing additives

Question 62

A fluid is considered to be at rest when:

Accepted Answer

There is zero shear stress at all points within the fluid

Answer

Its pressure is constant throughout

Answer

Its acceleration is zero

Answer

Its velocity is zero at all points

Question 63

Which of the following equations represents Bernoulli's principle?

Accepted Answer

P + (1/2)ρv^2 + ρgy = constant

Answer

τ = μ(du/dy)

Answer

F = ma

Answer

Q = Av

Question 64

The head loss due to friction in a pipe is given by:

Accepted Answer

hf = f(L/D)(v^2/2g)

Answer

hf = Q/A

Answer

hf = (1/2)ρv^2

Answer

hf = ρgh