   ## Hydraulics MCQ Practice Questions (Civil Engineering) Set 8

##### In fluids, steady flow occurs when:

Options are :

• Velocity vector remains constant at a point
• Conditions of flow do not change with time at a point
• Conditions of flow change steadily with time
• Conditions of flow remain the same at adjacent point

Answer :Conditions of flow do not change with time at a point

##### The main assumption of Bernoulli's equation is:

Options are :

• The velocity of energy of liquid particle, across any cross-section of a pipe is uniform
• There is no loss of energy of the liquid while flowing
• No external force except the gravity acts on the liquid
• All the above

##### For most economical rectangular section of a channel, the depth is kept:

Options are :

• Half the width
• One-fourth of the width
• Three times the hydraulic radius
• Hydraulic mean depth
• None of these

Options are :

• 31.3 m/sec
• 31.1 m/sec
• 31.4 m/sec
• 31.2 m/sec

Options are :

• 2.5 m^(3)
• 2.0 m^(3)
• 4.0 m^(3)
• 3.0 m^(3)

Options are :

• A
• D
• B
• C

##### Liquids:

Options are :

• Do not occupy definite shape
• Are not affected by change in pressure and temperature
• None of these
• Cannot be compressed

Answer :Do not occupy definite shape

##### Euler's equation for the motion of liquids assumes that:

Options are :

• Fluid is viscous
• Fluid is homogeneous and incompressible
• Velocity of flow is non-uniform over the section
• Flow is unsteady along the stream line

Answer :Fluid is homogeneous and incompressible

##### When water flows over a rectangular suppressed weir, the negative pressure created beneath the nappe:

Options are :

• None of these
• Increases the discharge
• Decreases the discharge
• Does not effect the discharge

##### Cavitation is caused by:

Options are :

• High velocity
• None of these
• High pressure
• Low velocity
• Low pressure

##### The velocity of the fluid particle at the centre of the pipe section, is:

Options are :

• Maximum
• Equal throughout
• None of these
• Minimum

Options are :

##### In a centrifugual pump casing, the flow of water leaving the impeller, is:

Options are :

• Forced vertex
• Rectilinear flow
• Free vortex motion

Options are :

• 459 kg
• 945 kg
• 95.4 kg
• 954 kg
• 549 kg

##### Due to decrease of diameter of the droplet, inside pressure intensity:

Options are :

• Decreases
• Remains unaffected
• Increases
• None of these

Options are :

• 0.25 s
• 1.5 s
• 1.0 s
• 0.50 s

Options are :

• 3.0 m
• 2 m
• 4.0 m
• 2.5 m

Options are :

• A
• D
• C
• B

##### Mercury is generally used in barometers because:

Options are :

• It is a best liquid
• None of these
• Its vapour pressure is practically zero
• The height of the barometer will be less

Answer :Its vapour pressure is practically zero The height of the barometer will be less

##### The mouth piece shown in the below figure is generally known as: Larger image Options are :

• Re-entrant mouth piece
• All the above
• Internal mouth piece
• Borda's mouth piece

##### If cohesion between the molecules of a fluid is more than adhesion between the fluid and glass, the free level of fluid in a dipped glass tube will be:

Options are :

• Same as the surface of liquid
• Lower than the surface of liquid
• None of these
• Higher than the surface of liquid

Answer :Lower than the surface of liquid

##### Flow in pipes is laminar if Reynold number is:

Options are :

• Less than 2100
• None of these
• Between 2100 and 3000
• More than 3000

##### Hydraulic ram is a device:

Options are :

• For accelerating water flow
• For lifting water without an electric motor
• None of these

Answer :For lifting water without an electric motor

##### If u, v, w are the components of the velocity v of a moving particle, the equation Larger image represents:

Options are :

• None of these
• Two dimensional flow
• One diamensional flow
• Three dimensional flow

##### In pipe lines, a surge tank is provided:

Options are :

• To remove the frictional loss in pipe
• To overflow the pipe line when suddenly closed
• To relieve the pressure due to water hammer

Answer :To relieve the pressure due to water hammer

##### For critical depth of flow of water in open channels, fc the specific energy must be:

Options are :

• Minimum
• Maximum
• None of these
• Average of maximum and minimum

Options are :

• D
• C
• A
• B

##### An orifice is taken as large if:

Options are :

• (H2 - H1) > H/4
• (H2 - H1) > H/2
• (H2 - H1) > H/3
• (H2 - H1) > H

Answer :(H2 - H1) > H/3

##### Mach number is the ratio of inertia force to:

Options are :

• Gravitational force
• Surface tension
• Viscosity
• Elasticity

##### The continuity equation:

Options are :

• Relates the momentum per unit volume between two points on a stream line
• Requires that Newton's second law of motion be satisfied at every point in fluid
• Expresses the relationship between work and energy
• Relates mass rate of flow along a stream line

Answer :Relates mass rate of flow along a stream line

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