Mercury is often used in barometer because
It is the best liquid
The height of barometer will be less
Its vapour pressure is so low that it may be neglected
Both (B) and (C)
Correct Answer :
D. Both (B) and (C)
Related Questions
The vapour pressure over the concave surface is
Less man the vapour pressure over the plane surface
Equal to the vapour pressure over the plane surface
Greater than the vapour pressure over the plane surface
Zero
Buoyant force is
The resultant force acting on a floating body
The resultant force on a body due to the fluid surrounding it
Equal to the volume of liquid displaced
The force necessary to maintain equilibrium of a submerged body
Manometer is used to measure
Pressure in pipes, channels etc.
Atmospheric pressure
Very low pressure
Difference of pressure between two points
Choose the wrong statement
The horizontal component of the hydrostatic force on any surface is equal to the normal force on the vertical projection of the surface
The horizontal component acts through the center of pressure for the vertical projection
The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area
The vertical component passes through the center of pressure of the volume
For a floating body to be in stable equilibrium, its metacentre should be
Below the center of gravity
Below the center of buoyancy
Above the center of buoyancy
Above the center of gravity
Reynold's number is the ratio of inertia force to
Pressure force
Elastic force
Gravity force
Viscous force
A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm² and a volume of 0.039 m3 at 150 kg/cm². The bulk modulus of elasticity of liquid is
400 kg/cm²
4000 kg/cm²
40 × 10⁵ kg/cm²
40 × 10⁶ kg/cm²
The line of action of the buoyant force acts through the
Centroid of the volume of fluid vertically above the body
Centre of the volume of floating body
Center of gravity of any submerged body
Centroid of the displaced volume of fluid
A structure used to dam up a stream or river over which the water flows is called
Orifice
Notch
Weir
Dam
The pressure of liquid at throat in a Venturimeter is __________ than that at inlet.
Higher
Lower
Same
None of these
The pressure intensity in kN/m2 (or kPa) at any point in a liquid is (where w = Specific weight of liquid, and h = Depth of liquid from the surface)
w
wh
w/h
h/w
The Euler's equation for the motion of liquids is based upon the assumption that
The fluid is non - viscous, homogeneous and incompressible
The velocity of flow is uniform over the section
The flow is continuous, steady and along the stream line
All of the above
A manometer is used to measure
Atmospheric pressure
Pressure in pipes and channels
Pressure in Venturimeter
Difference of pressures between two points in a pipe
An opening in the side of a tank or vessel such that the liquid surface with the tank is below the top edge of the opening, is called
Weir
Notch
Orifice
None of these
Dynamic viscosity of most of the gases with rise in temperature
Increases
Decreases
Remain unaffected
Unpredictable
Dimensions of surface tension are
ML°T⁻²
ML°T
ML r²
ML²T²
In order to measure the flow with a Venturimeter, it is installed in
Horizontal line
Inclined line with flow upwards
Inclined line with flow downwards
Any direction and in any location
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
The divergent portion of a Venturimeter is made longer than convergent portion in order to
Avoid the tendency of breaking away the stream of liquid
To minimise frictional losses
Both (A) and (B)
None of these
When a tank containing liquid moves with an acceleration in the horizontal direction, then the free surface of the liquid
Remains horizontal
Becomes curved
Falls on the front end
Falls on the back end
For hypersonic flow, the Mach number is
Unity
Greater than unity
Greater than 2
Greater than 4
The mercury does not wet the glass. This is due to the property of the liquid known as
Cohesion
Adhesion
Viscosity
Surface tension
The flow in which the velocity vector is identical in magnitude and direction at every point, for any given instant, is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
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
The discharge through a channel of trapezoidal section is maximum when
Width of channel at the top is equal to twice the width at the bottom
Depth of channel is equal to the width at the bottom
The sloping side is equal to half the width at the top
The sloping side is equal to the width at the bottom
The flow which neglects changes in a transverse direction is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
In a forced vortex, the velocity of flow everywhere within the fluid is
Maximum
Minimum
Zero
Nonzero finite
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
A flow in which the volume of a fluid and its density does not change during the flow is called _________ flow.
Incompressible
Compressible
Viscous
None of these
The normal stress is same in all directions at a point in a fluid
Only when the fluid is frictionless
Only when the fluid is incompressible and has zero viscosity
When there is no motion of one fluid layer relative to an adjacent layer
Irrespective of the motion of one fluid layer relative to an adjacent layer