Rain drops are spherical because of
Viscosity
Air resistance
Surface tension forces
Atmospheric pressure
Correct Answer :
C. Surface tension forces
Related Questions
Surface tension
Acts in the plane of the interface normal to any line in the surface
Is also known as capillarity
Is a function of the curvature of the interface
Decreases with fall in temperature
Choose the wrong statement
The center of buoyancy is located at the center of gravity of the displaced liquid
For stability of a submerged body, the center of gravity of body must lie directly below the center of buoyancy
If C.G. and center of buoyancy coincide, the submerged body must lie at neutral equilibrium for all positions
All floating bodies are stable
Liquids transmit pressure equally in all the directions. This is according to
Boyle's law
Archimedes principle
Pascal's law
Newton's formula
The critical depth meter is used to measure
Velocity of flow in an open channel
Depth of flow in an open channel
Hydraulic jump
Depth of channel
When a cylindrical vessel containing liquid is revolved about its vertical axis at a constant angular velocity, the pressure
Varies as the square of the radial distance
Increases linearly as its radial distance
Increases as the square of the radial distance
Decreases as the square of the radial distance
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
500 kg
1000 kg
1500 kg
2000 kg
The value of coefficient of velocity for a sharp edged orifice __________ with the head of water.
Decreases
Increases
Remain same
None of these
The pressure measured with the help of a Piezometer tube is in
N/mm2
N/m2
Head of liquid
All of these
The pressure measured with the help of a pressure gauge is called
Atmospheric pressure
Gauge pressure
Absolute pressure
Mean pressure
The flow in which conditions do not change with time at any point, is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
According to Manning's formula, the discharge through an open channel is (where M = Manning's constant)
A × M × m1/2 × i2/3
A × M × m2/3 × i1/2
A1/2 × M2/3 × m × i
A2/3 × M1/3 × m × i
The flow in a pipe is turbulent when Reynold number is
Less than 2000
Between 2000 and 2800
More than 2800
None of these
An orifice is said to be large, if
The size of orifice is large
The velocity of flow is large
The available head of liquid is more than 5 times the height of orifice
The available head of liquid is less than 5 times the height of orifice
The speed of sound in a ideal gas varies directly as its
Absolute temperature
Temperature
Density
Modulus of elasticity
The maximum discharge over a broad crested weir is
0.384 Cd × L × H1/2
0.384 Cd × L × H3/2
1.71 Cd × L × H1/2
1.71 Cd × L × H3/2
A large Reynold number is indication of
Smooth and streamline flow
Laminar flow
Steady flow
Highly turbulent flow
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
Steady flow
Turbulent flow
Vortex flow
Uniform flow
A weir is said to be broad 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
Bernoulli's equation is applied to
Venturimeter
Orifice meter
Pitot tube
All of these
The mass of 2.5 m3 of a certain liquid is 2 tonnes. Its mass density is
200 kg/m3
400 kg/m3
600 kg/m3
800 kg/m3
Dynamic viscosity of most of the gases with rise in temperature
Increases
Decreases
Remain unaffected
Unpredictable
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)
4wd/σ cosα
σ cosα/4wd
4σ cosα/wd
wd/4σ cosα
The magnitude of water hammer depends upon the
Elastic properties of the pipe material
Elastic properties of the liquid flowing through the pipe
Speed at which the valve is closed
All of the above
Piezometer is used to measure
Pressure in pipe, channels etc.
Atmospheric pressure
Very low pressures
Difference of pressure between two points
For manometer, a better liquid combination is one having
Higher surface tension
Lower surface tension
Surface tension is no criterion
High density and viscosity
Coefficient of velocity is defined as the ratio of
Actual velocity of jet at vena contracta to the theoretical velocity
Area of jet at vena contracta to the area of orifice
Actual discharge through an orifice to the theoretical discharge
None of the above
A balloon lifting in air follows the following principle
Law of gravitation
Archimedes principle
Principle of buoyancy
All of the above
An open tank containing liquid is moving with an acceleration on an inclined plane. The inclination of the free surface of the liquid will be __________ to the acceleration of the tank.
Equal to
Directly proportional
Inversely proportional
None of these
Which of the following instrument can be used for measuring speed of a submarine moving in deep sea?
Venturimeter
Orifice plate
Hot wire anemometer
Pitot tube
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
v₁²/2g
v₂²/2g
0.5 v₁²/2g
0.375 v₂²/2g