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4

The length AB of a pipe ABC in which the liquid is flowing has diameter (d1) and is suddenly contracted to diameter (d2) at B which is constant for the length BC. The loss of head due to sudden contraction, assuming coefficient of contraction as 0.62, is

A. v₁²/2g

B. v₂²/2g

C. 0.5 v₁²/2g

D. 0.375 v₂²/2g

Correct Answer :

D. 0.375 v₂²/2g


Related Questions

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4

In an external mouthpiece, the absolute pressure head at vena contracta is __________ the atmospheric pressure head by an amount equal to 0.89 times the height of the liquid, above the vena contracta.

A. Less than

B. More than

C. Equal to

D. None of these

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4

A glass tube of small diameter (d) is dipped in fluid. The height of rise or fall in the tube given by (where w = Specific weight of liquid, α = Angle of contact of the liquid surface, and σ = Surface tension)

A. 4wd/σ cosα

B. σ cosα/4wd

C. 4σ cosα/wd

D. wd/4σ cosα

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4

The total pressure on the surface of a vertical sluice gate 2 m x 1 m with its top 2 m surface being 0.5 m below the water level will be

A. 500 kg

B. 1000 kg

C. 1500 kg

D. 2000 kg

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4

The hydraulic gradient line lies over the centre line of the pipe by an amount equal to the

A. Pressure head

B. Velocity head

C. Pressure head + velocity head

D. Pressure head - velocity head

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4

The tendency of a liquid surface to contract is due to the following property

A. Cohesion

B. Adhesion

C. Viscosity

D. Surface tension

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4

For a floating body to be in equilibrium

A. Meta centre should be above e.g.

B. Centre of buoyancy and e.g. must lie on same vertical plane

C. A righting couple should be formed

D. All of the above

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4

In a footstep bearing, if the speed of the shaft is doubled, then the torque required to overcome the viscous resistance will be

A. Double

B. Four times

C. Eight times

D. Sixteen times

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4

In a depressed nappe

A. The pressure below the nappe is atmospheric

B. The pressure below the nappe is negative

C. The pressure above the nappe is atmospheric

D. The pressure above the nappe is negative

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4

In open channels, the specific energy is the

A. Total energy per unit discharge

B. Total energy measured with respect to the datum passing through the bottom of the channel

C. Total energy measured above the horizontal datum

D. Kinetic energy plotted above the free surface of water

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4

The critical depth meter is used to measure

A. Velocity of flow in an open channel

B. Depth of flow in an open channel

C. Hydraulic jump

D. Depth of channel

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4

The continuity equation is connected with

A. Open channel/pipe flow

B. Compressibility of fluids

C. Conservation of mass

D. Steady/unsteady flow

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4

When a cylindrical vessel containing liquid is resolved, the surface of the liquid takes the shape of

A. A triangle

B. A paraboloid

C. An ellipse

D. None of these

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4

The stability of a dam is checked for

A. Tension at the base

B. Overturning of the wall or dam

C. Sliding of the wall or dam

D. All of these

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4

Barometer is used to measure

A. Velocity of liquid

B. Atmospheric pressure

C. Pressure in pipes and channels

D. Difference of pressure between two points in a pipe

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4

The siphon will work satisfactorily, if the minimum pressure in the pipe is __________ vapour pressure of liquid.

A. Equal to

B. Less than

C. More than

D. None of these

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4

A manometer is used to measure

A. Atmospheric pressure

B. Pressure in pipes and channels

C. Pressure in Venturimeter

D. Difference of pressures between two points in a pipe

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4

When a tank containing liquid moves with an acceleration in the horizontal direction, then the free surface of the liquid

A. Remains horizontal

B. Becomes curved

C. Falls on the front end

D. Falls on the back end

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4

The specific gravity of water is taken as

A. 0.001

B. 0.01

C. 0.1

D. 1

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4

The power transmitted through the pipe is maximum when the head lost due to friction is equal to

A. One-fourth of the total supply head

B. One-third of the total supply head

C. One-half of the total supply head

D. Two-third of the total supply head

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4

The mass per unit volume of a liquid at a standard temperature and pressure is called

A. Specific weight

B. Mass density

C. Specific gravity

D. None of these

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4

Newton's law of viscosity is a relationship between

A. Shear stress and the rate of angular distortion

B. Shear stress and viscosity

C. Shear stress, velocity and viscosity

D. Pressure, velocity and viscosity

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4

A flow in which the quantity of liquid flowing per second is constant, is called __________ flow.

A. Steady

B. Streamline

C. Turbulent

D. Unsteady

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4

The efficiency of power transmission through pipe is (where H = Total supply head, and hf = Head lost due to friction in the pipe)

A. (H - hf )/H

B. H/(H - hf )

C. (H + hf )/H

D. H/(H + hf )

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4

The loss of head at exit of a pipe is (where v = Velocity of liquid in the pipe)

A. v²/2g

B. 0.5v²/2g

C. 0.375v²/2g

D. 0.75v²/2g

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4

In a static fluid

A. Resistance to shear stress is small

B. Fluid pressure is zero

C. Linear deformation is small

D. Only normal stresses can exist

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4

At the center line of a pipe flowing under pressure where the velocity gradient is zero, the shear stress will be

A. Minimum

B. Maximum

C. Zero

D. Could be any value

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4

The total energy line lies over the hydraulic gradient line by an amount equal to the

A. Pressure head

B. Velocity head

C. Pressure head + velocity head

D. Pressure head - velocity head

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4

The discharge over the trapezoidal notch is equal to the discharge over the rectangular notch __________ the discharge over the triangular notch.

A. Plus

B. Minus

C. Divide

D. None of these

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4

To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more than

A. 2.4 m above the hydraulic gradient

B. 6.4 m above the hydraulic gradient

C. 10.0 m above the hydraulic gradient

D. 5.0 above the hydraulic gradient

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4

An average value of coefficient of velocity is

A. 0.62

B. 0.76

C. 0.84

D. 0.97