50 MCQs on Hydraulics & Fluid Mechanics
Properties of Fluids (10 Questions)
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The property of a fluid which enables it to resist tensile stress is:
A) Density
B) Viscosity
C) Compressibility
D) Cohesion
Ans: D -
The unit of dynamic viscosity in SI units is:
A) N·s/m²
B) Pa
C) m²/s
D) N/m²
Ans: A -
A fluid is defined as a substance that:
A) Cannot flow
B) Has no viscosity
C) Continuously deforms under shear stress
D) Cannot be compressed
Ans: C -
Kinematic viscosity is defined as:
A) μρ
B) μ/ρ
C) ρ/μ
D) μ + ρ
Ans: B -
The specific weight of water is:
A) 9.81 N/m³
B) 1000 N/m³
C) 9810 N/m³
D) 1 N/m³
Ans: C -
Surface tension is measured in:
A) N/m²
B) N/m
C) m²/s
D) N
Ans: B -
The bulk modulus of elasticity for an incompressible fluid is:
A) Zero
B) Infinite
C) Very low
D) Equal to its density
Ans: B -
The ratio of specific weight to density is:
A) Gravity
B) Specific gravity
C) Compressibility
D) Viscosity
Ans: A -
A fluid with no resistance to shear stress is called:
A) Newtonian fluid
B) Ideal fluid
C) Real fluid
D) Viscous fluid
Ans: B -
Specific gravity is the ratio of:
A) Weight of fluid to volume
B) Density of fluid to water
C) Specific weight to weight
D) Viscosity of fluid to water
Ans: B
🌊 Hydrostatics & Pressure Measurement (10 Questions)
-
Pascal’s law is valid for:
A) Gases only
B) Fluids at rest
C) Moving fluids
D) Ideal gases
Ans: B -
Pressure intensity in a static fluid increases with:
A) Temperature
B) Depth
C) Volume
D) Velocity
Ans: B -
The unit of pressure is:
A) Newton
B) Watt
C) Pascal
D) Joule
Ans: C -
Barometer is used to measure:
A) Vacuum pressure
B) Gauge pressure
C) Absolute pressure
D) Atmospheric pressure
Ans: D -
Piezometer cannot be used for:
A) Open tanks
B) High-pressure measurement
C) Low pressure
D) Measuring small heads
Ans: B -
Manometers work on the principle of:
A) Archimedes' law
B) Bernoulli's equation
C) Hydrostatic law
D) Pascal’s law
Ans: C -
A U-tube manometer contains:
A) Only mercury
B) Two fluids
C) One fluid
D) No fluid
Ans: B -
Absolute pressure =
A) Atmospheric + Gauge pressure
B) Gauge - Atmospheric
C) Gauge pressure only
D) Atmospheric pressure only
Ans: A -
The center of pressure on a submerged plane surface lies:
A) At centroid
B) Above centroid
C) Below centroid
D) On surface
Ans: C -
Hydrostatic force on a vertical submerged surface is:
A) Area × depth to centroid × ρg
B) Area × ρg only
C) Area × surface pressure only
D) Volume × ρg
Ans: A
🚰 Flow through Pipes & Channels (10 Questions)
-
Flow is said to be laminar when Reynolds number is:
A) < 2000
B) > 4000
C) = 4000
D) = 2000
Ans: A -
Continuity equation is based on the principle of:
A) Conservation of mass
B) Conservation of energy
C) Conservation of momentum
D) Thermodynamics
Ans: A -
Head loss in pipe flow is calculated by:
A) Bernoulli’s equation
B) Darcy-Weisbach equation
C) Pascal’s law
D) Newton’s law
Ans: B -
The unit of discharge is:
A) m/s
B) m²
C) m³/s
D) m
Ans: C -
Hydraulic gradient line represents:
A) Velocity head
B) Pressure head
C) Total energy
D) Datum head
Ans: B -
The flow through a channel is said to be critical when:
A) Froude number = 1
B) Reynolds number < 2000
C) Flow is turbulent
D) Slope is zero
Ans: A -
A sudden expansion in a pipeline causes:
A) Increase in velocity
B) Increase in pressure
C) Energy gain
D) None
Ans: B -
Most economical section in open channel for rectangular section occurs when:
A) b = 2y
B) b = y
C) b = y²
D) b = y/2
Ans: A -
In turbulent flow, head loss is proportional to:
A) v
B) v²
C) 1/v
D) v³
Ans: B -
Hydraulic radius is given by:
A) Area / Perimeter
B) Velocity × Depth
C) Volume / Area
D) Slope × Depth
Ans: A
🌀 Bernoulli’s Equation (10 Questions)
-
Bernoulli's equation is valid for:
A) Compressible flow
B) Rotational flow
C) Inviscid and steady flow
D) Unsteady flow
Ans: C -
Bernoulli’s equation is derived from:
A) Newton’s second law
B) First law of thermodynamics
C) Conservation of momentum
D) Conservation of energy
Ans: D -
Bernoulli’s equation assumes:
A) Viscous losses
B) No heat transfer
C) Compressible fluid
D) Constant temperature
Ans: B -
The term z in Bernoulli’s equation refers to:
A) Pressure head
B) Elevation head
C) Velocity head
D) Loss head
Ans: B -
Venturimeter is based on:
A) Continuity equation
B) Bernoulli’s equation
C) Newton’s law
D) Reynolds number
Ans: B -
In Bernoulli's equation, the pressure head is given by:
A) P/ρg
B) ρgP
C) ρ/Pg
D) Pg/ρ
Ans: A -
Flow velocity is maximum where:
A) Pressure is minimum
B) Pressure is maximum
C) Elevation is highest
D) Energy loss is maximum
Ans: A -
The velocity head is represented by:
A) v
B) v²/2g
C) v²/g
D) 2gv
Ans: B -
In a horizontal pipe, if pressure decreases, then velocity:
A) Increases
B) Decreases
C) Constant
D) Becomes zero
Ans: A -
Bernoulli’s equation fails when:
A) Flow is steady
B) Flow is frictionless
C) Flow has energy loss
D) Flow is irrotational
Ans: C
⚙️ Hydraulic Machines (10 Questions)
-
A reciprocating pump is:
A) Positive displacement
B) Dynamic
C) Centrifugal
D) Turbine
Ans: A -
The efficiency of a turbine is maximum when:
A) Speed is zero
B) Head is zero
C) Discharge is maximum
D) Velocity triangles are symmetrical
Ans: D -
The device used to store energy in hydraulic systems is:
A) Nozzle
B) Accumulator
C) Turbine
D) Draft tube
Ans: B -
In Pelton wheel, energy is extracted by:
A) Impulse
B) Reaction
C) Friction
D) Cavitation
Ans: A -
Francis turbine is a:
A) Impulse turbine
B) Reaction turbine
C) Axial flow
D) Crossflow
Ans: B -
Cavitation in pumps occurs when:
A) Pressure drops below vapor pressure
B) Velocity is zero
C) Head is maximum
D) Flow is laminar
Ans: A -
Priming is necessary in:
A) Reciprocating pumps
B) Jet pumps
C) Centrifugal pumps
D) Turbines
Ans: C -
Unit of pump power is:
A) Pascal
B) Newton
C) Watt
D) kg
Ans: C -
Manometric head is:
A) Total head of pump
B) Head measured by manometer
C) Sum of suction and delivery heads
D) Total dynamic head
Ans: C -
Efficiency of centrifugal pump is the ratio of:
A) Work done by impeller to power input
B) Head to discharge
C) Output to speed
D) Flow rate to velocity
Ans: A