Cavitation is caused by
High velocity
High pressure
Weak material
Low pressure
Correct Answer :
D. Low pressure
Related Questions
The efficiency of power transmission through pipe is (where H = Total supply head, and hf = Head lost due to friction in the pipe)
(H - hf )/H
H/(H - hf )
(H + hf )/H
H/(H + hf )
The pressure at a point in a fluid will not be same in all the directions when the fluid is
Moving
Viscous
Viscous and static
Viscous and moving
A streamline is defined as the line
Parallel to central axis flow
Parallel to outer surface of pipe
Of equal velocity in a flow
Along which the pressure drop is uniform
A pitot tube is used to measure the
Velocity of flow at the required point in a pipe
Pressure difference between two points in a pipe
Total pressure of liquid flowing in a pipe
Discharge through a pipe
A compound pipe of diameter d1, d2 and d3 having lengths l1, l2 and l3 is to be replaced by an equivalent pipe of uniform diameter d and of the same length (l) as that of the compound pipe. The size of the equivalent pipe is given by
l/d² = (l₁/d₁²) + (l₂/d₂²) + (l₃/d₃²)
l/d³ = (l₁/d₁³) + (l₂/d₂³) + (l₃/d₃³)
l/d⁴ = (l₁/d₁⁴) + (l₂/d₂⁴) + (l₃/d₃⁴)
l/d⁵ = (l₁/d₁⁵) + (l₂/d₂⁵) + (l₃/d₃⁵)
In order that flow takes place between two points in a pipeline, the differential pressure between these points must be more than
Frictional force
Viscosity
Surface friction
All of the above
Falling drops of water become spheres due to the property of
Surface tension of water
Compressibility of water
Capillarity of water
Viscosity of water
The tendency of a liquid surface to contract is due to the following property
Cohesion
Adhesion
Viscosity
Surface tension
A vessel of 4 m3 contains oil which weighs 30 kN. The specific weight of the oil is
4.5 kN/m3
6 kN/m3
7.5 kN/m3
10 kN/m3
The discharge over a rectangular notch is (where b = Width of notch, and H = Height of liquid, above the sill of the notch)
(2/3) Cd × b × √(2gH)
(2/3) Cd × b × √(2g) × H
(2/3) Cd × b × √(2g) × H3/2
(2/3) Cd × b × √(2g) × H2
According to Bazin's formula, the discharge over a rectangular weir is mL2g x H3/2where m is equal to
0.405 + (0.003/H)
0.003 + (0.405/H)
0.405 + (H/0.003)
0.003 + (H/0.405)
The flow in which each liquid particle has a definite path and their paths do not cross each other is called
One dimensional flow
Streamline flow
Steady flow
Turbulent flow
The coefficient of discharge in case of internal mouthpiece is __________ that of external mouthpiece.
Less than
More than
Equal to
None of these
Center of buoyancy is the
Centroid of the displaced volume of fluid
Center of pressure of displaced volume
Does not exist
None of the above
The value of bulk modulus of a fluid is required to determine
Reynold's number
Froude's number
Mach number
Euler's number
The total pressure on a horizontally immersed surface is (where w = Specific weight of the liquid, A = Area of the immersed surface, and x = Depth of the centre of gravity of the immersed surface from the liquid surface)
wA
wx
wAx
wA/x
A model of torpedo is tested in a towing tank at a velocity of 25 m/sec. The prototype is expected to attain a velocity of 5 m/sec. What model scale has been used?
1 : 5
1 : 2.5
1 : 25
1 : √5
The conditions for the stable equilibrium of a floating body are
The metacentre should lie above the center of gravity
The center of buoyancy and the center of gravity must lie on the same vertical line
A righting couple should be formed
All the above are correct
The specific weight of water in S.I. units is taken as
9.81 kN/m3
9.81 × 103 N/m3
9.81 × 10-6 N/mm3
Any one of these
The difference of pressure between the inside and outside of a liquid drop is
p = T × r
p = T/r
p = T/2r
p = 2T/r
The centre of gravity of the volume of the liquid displaced is called
Centre of pressure
Centre of buoyancy
Metacentre
None of these
Surface energy per unit area of a surface is numerically equal to
Atmospheric pressure
Surface tension
Force of adhesion
Force of cohesion
Alcohol is used in manometers because
It has low vapour pressure
It is clearly visible
It has low surface tension
It can provide longer column due to low density
One poise is equal to
0.1 N-s/m2
1 N-s/m2
10 N-s/m2
100 N-s/m2
One cubic metre of water weighs
100 litres
250 litres
500 litres
1000 litres
All the terms of energy in Bernoulli's equation have dimension of
Energy
Work
Mass
Length
A square surface 3 m × 3 m lies in a vertical line in water pipe its upper edge at water surface. The hydrostatic force on square surface is
9,000 kg
13,500 kg
18,000 kg
27,000 kg
The siphon will work satisfactorily, if the minimum pressure in the pipe is __________ vapour pressure of liquid.
Equal to
Less than
More than
None of these
The stress-strain relation of the Newtonian fluid is
Linear
Parabolic
Hyperbolic
Inverse type
The discharge through a siphon spillway is
Cd × a × √(2gH)
Cd × a × √(2g) × H3/2
Cd × a × √(2g) × H2
Cd × a × √(2g) × H5/2