The tendency of a liquid surface to contract is due to the following property
Cohesion
Adhesion
Viscosity
Surface tension
Correct Answer :
D. Surface tension
Related Questions
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.
Less than
More than
Equal to
None of these
A flow through an expanding tube at constant rate is called
Steady uniform flow
Steady non-uniform flow
Unsteady uniform flow
Unsteady non-uniform flow
Venturimeter is used to
Measure the velocity of a flowing liquid
Measure the pressure of a flowing liquid
Measure the discharge of liquid flowing in a pipe
Measure the pressure difference of liquid flowing between two points in a pipe line
Specific weight of water in S.I. units is equal to
1000 N/m3
10000 N/m3
9.81 × 103 N/m3
9.81 × 10⁶ N/m3
The centre of gravity of the volume of the liquid displaced by an immersed body is called
Centre of gravity
Centre of pressure
Metacentre
Centre of buoyancy
According to Bernoulli's equation
Z + p/w + v²/2g = constant
Z + p/w - v²/2g = constant
Z - p/w + v²/2g = constant
Z - p/w - v²/2g = constant
If the coefficient of discharge is 0.6, then the discharge over a right angled notch is
0.417 H5/2
1.417 H5/2
4.171 H5/2
7.141 H5/2
The meatcentric height of a ship is 0.6 m and the radius of gyration is 4 m. The time of rolling of a ship is
4.1 s
5.2 s
10.4 s
14.1 s
The sheet of water flowing over a notch or a weir is known as
Sill or crest
Nappe or vein
Orifice
None of these
A differential manometer is used to measure
Atmospheric pressure
Pressure in pipes and channels
Pressure in Venturimeter
Difference of pressures between two points in a pipe
The angle of contact in case of a liquid depends upon
The nature of the liquid and the solid
The material which exists above the free surface of the liquid
Both of die above
Any one of the above
The discharge through a channel of rectangular section will be maximum, if
Its depth is twice the breadth
Its breadth is twice the depth
Its depth is thrice the breadth
Its breadth is thrice the depth
The total pressure on the top of a closed cylindrical vessel of radius (r) completely filled up with liquid of specific weight (w) and rotating at (ω) rad/s about its vertical axis, is
π w ω² r²/4g
π w ω² r³/4g
π w ω² r⁴/4g
π w ω² r²/2g
In a short cylindrical external mouthpiece, the vena contracta occurs at a distance __________ the diameter of the orifice from the outlet of orifice.
Equal to
One-fourth
One-third
One-half
Froude number is significant in
Supersonics, as with projectile and jet propulsion
Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect as with ship's hulls
All of the above
In a static fluid
Resistance to shear stress is small
Fluid pressure is zero
Linear deformation is small
Only normal stresses can exist
Newton's law of viscosity is a relationship between
Shear stress and the rate of angular distortion
Shear stress and viscosity
Shear stress, velocity and viscosity
Pressure, velocity and viscosity
The discharge over the trapezoidal notch is equal to the discharge over the rectangular notch __________ the discharge over the triangular notch.
Plus
Minus
Divide
None of these
Rain drops are spherical because of
Viscosity
Air resistance
Surface tension forces
Atmospheric pressure
A tank of uniform cross-sectional area (A) containing liquid upto height (H1) has an orifice of cross-sectional area (a) at its bottom. The time required to bring the liquid level from H1 to H2 will be
2A × √H₁/Cd × a × √(2g)
2A × √H₂/Cd × a × √(2g)
2A × (√H₁ - √H₂)/Cd × a × √(2g)
2A × (√H3/2 - √H3/2)/Cd × a × √(2g)
The diameter of the nozzle (d) for maximum transmission of power is given by (where D = Diameter of pipe, f = Darcys coefficient of friction for pipe, and l = Length of pipe)
d = (D⁵/8fl)1/2
d = (D⁵/8fl)1/3
d = (D⁵/8fl)1/4
d = (D⁵/8fl)1/5
An internal mouthpiece is said to be running free if the length of the mouthpiece is __________ the diameter of the orifice.
Less than twice
More than twice
Less than three times
More than three times
A weir is said to be narrow-crested weir, if the width of the crest of the weir is __________ half the height of water above the weir crest.
Equal to
Less than
More than
None of these
Two dimensional flows occurs when
The direction and magnitude of the velocity at all points are identical
The velocity of successive fluid particles, at any point, is the same at successive periods of time
The magnitude and direction of the velocity do not change from point to point in the fluid
The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
The capillary rise at 20°C in a clean glass tube of 1 mm bore containing water is approximately
5 mm
10 mm
20 mm
30 mm
The velocity at which the flow changes from laminar flow to turbulent flow is called
Critical velocity
Velocity of approach
Sub-sonic velocity
Super-sonic velocity
The time oscillation of a floating body with increase in meatcentric height will be
Same
Higher
Lower
Lower/higher depending on weight of body
The most efficient section of a channel is
Triangular
Rectangular
Square
Trapezoidal
The bulk modulus of elasticity with increase in pressure
Increases
Decreases
Remain constant
Increases first up to certain limit and then decreases
In case of flow through parallel pipes,
The head loss for all the pipes is same
The total discharge is equal to the sum of discharges in the various pipes
The total head loss is the sum of head losses in the various pipes
Both (A) and (B)