Home » Mechanical Engineering » Mechanical Engineering MCQ » Hydraulics And Fluid Mechanics

# 650 Important Hydraulics And Fluid Mechanics MCQ Question and Answer | PDF Free Download

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

• ASteady
• BStreamline
• CTurbulent
• DUnsteady
Correct Answer : (A)

Steady

Explanation:

### 2.The Cipoletti weir is a __________ weir.

• ARectangular
• BTriangular
• CTrapezoidal
• DCircular
Correct Answer : (C)

Trapezoidal

Explanation:

### 3.A hydraulic ram is a device used to

• AStore the energy of water
• BIncrease the pressure of water
• CTo lift water from deep wells
• DTo lift small quantity of water to a greater height when a large quantity of water is available at a smaller height
Correct Answer : (D)

To lift small quantity of water to a greater height when a large quantity of water is available at a smaller height

Explanation:

### 4.According to the principle of buoyancy a body totally or partially immersed in a fluid will be lifted up by a force equal to

• AThe weight of the body
• BMore than the weight of the body
• CLess than the weight of the body
• DWeight of the fluid displaced by the body
Correct Answer : (D)

Weight of the fluid displaced by the body

Explanation:

### 5.The tangential velocity of the water element having a free vortex is

• ADirectly proportional to its distance from the centre
• BInversely proportional to its distance from the centre
• CDirectly proportional to its distance2 from the centre
• DInversely proportional to its distance2 from the centre
Correct Answer : (B)

Inversely proportional to its distance from the centre

Explanation:

### 6.The buoyancy depends upon the

• AWeight of the liquid displaced
• BPressure with which the liquid is displaced
• CViscosity of the liquid
• DCompressibility of the liquid
Correct Answer : (A)

Weight of the liquid displaced

Explanation:

### 7.The magnitude of water hammer depends upon the

• AElastic properties of the pipe material
• BElastic properties of the liquid flowing through the pipe
• CSpeed at which the valve is closed
• DAll of the above
Correct Answer : (D)

All of the above

Explanation:

### 8.The width of the bucket for a Pelton wheel is generally ________ the diameter of jet.

• ADouble
• BThree times
• CFour times
• DFive times
Correct Answer : (D)

Five times

Explanation:

### 9.The depth of the bucket for a Pelton wheel is generally _________ the diameter of jet.

• AEqual to
• B1.2 times
• C1.8 times
• DDouble
Correct Answer : (B)

1.2 times

Explanation:

### 10.The speed of sound in a ideal gas varies directly as it’s

• AAbsolute temperature
• BTemperature
• CDensity
• DModulus of elasticity
Correct Answer : (A)

Absolute temperature

Explanation:

### 11.The difference of pressure between the inside and outside of a liquid drop is

• Ap = T × r
• Bp = T/r
• Cp = T/2r
• Dp = 2T/r
Correct Answer : (D)

p = 2T/r

Explanation:

### 12.When a body, floating in a liquid, is given a small angular displacement, it starts oscillating about a point known as

• ACentre of pressure
• BCentre of gravity
• CCentre of buoyancy
• DMetacentre
Correct Answer : (D)

Metacentre

Explanation:

### 13.Fluid is a substance that

• ACannot be subjected to shear forces
• BAlways expands until it fills any container
• CHas the same shear stress at a point regardless of its motion
• DCannot remain at rest under action of any shear force
Correct Answer : (D)

Cannot remain at rest under action of any shear force

Explanation:

### 14.The line of action of the buoyant force acts through the

• ACentroid of the volume of fluid vertically above the body
• BCentre of the volume of floating body
• CCenter of gravity of any submerged body
• DCentroid of the displaced volume of fluid
Correct Answer : (D)

Centroid of the displaced volume of fluid

Explanation:

### 15.If the ratios of all the corresponding linear dimensions are equal, then the model and the prototype are said to have

• AGeometric similarity
• BKinematic similarity
• CDynamic similarity
• DNone of these
Correct Answer : (A)

Geometric similarity

Explanation:

### 16.Meta-centric height is given as the distance between

• AThe center of gravity of the body and the metacenter
• BThe center of gravity of the body and the center of buoyancy
• CThe center of gravity of the body and the center of pressure
• DCenter of buoyancy and metacenter
Correct Answer : (A)

The center of gravity of the body and the metacenter

Explanation:

### 17.When a cylindrical vessel, containing some liquid, is rotated about its vertical axis, the liquid surface is depressed down at the axis of its rotation and rises up near the walls of the vessel on all sides. This type of flow is known as

• ASteady flow
• BTurbulent flow
• CVortex flow
• DUniform flow
Correct Answer : (C)

Vortex flow

Explanation:

### 18.Non uniform flow occurs when

• AThe direction and magnitude of the velocity at all points are identical
• BThe velocity of successive fluid particles, at any point, is the same at successive periods of time
• CVelocity, depth, pressure, etc. change from point to point in the fluid flow
• DThe fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Correct Answer : (C)

Velocity, depth, pressure, etc. change from point to point in the fluid flow

Explanation:

### 19.Steady flow occurs when

• AThe direction and magnitude of the velocity at all points are identical
• BThe velocity of successive fluid particles, at any point, is the same at successive periods of time
• CThe magnitude and direction of the velocity do not change from point to point in the fluid
• DThe fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Correct Answer : (B)

The velocity of successive fluid particles, at any point, is the same at successive periods of time

Explanation:

### 20.True one-dimensional flow occurs when

• AThe direction and magnitude of the velocity at all points are identical
• BThe velocity of successive fluid particles, at any point, is the same at successive periods of time
• CThe magnitude and direction of the velocity do not change from point to point in the fluid
• DThe fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Correct Answer : (A)

The direction and magnitude of the velocity at all points are identical

Explanation: