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
Correct Answer :
C. The sloping side is equal to half the width at the top
Related Questions
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)
Dynamic viscosity of most of the liquids with rise in temperature
Increases
Decreases
Remain unaffected
Unpredictable
The increase in pressure at the outer edge of a drum of radius (r) completely filled up with liquid of density (ρ) and rotating at (ω) rad/s is
ρ ω2 r2
2ρ ω2 r2
ρ ω2 r2/2
ρ ω2 r2/4
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 viscosity of a liquid __________ its rate of flow through a hole in a vessel.
Effects
Does not effect
Both A and B
None of these
The Francis formula for the discharge over Cipoletti weir is
1.84 LH1/2
1.84 LH
1.84 LH3/2
1.84 LH5/2
An ideal flow of any fluid must satisfy
Pascal law
Newton's law of viscosity
Boundary layer theory
Continuity equation
The density of water is 1000 kg/m3 at
0° C
0° K
4° C
20° C
The units of dynamic or absolute viscosity are
Metres² per sec
kg sec/meter
Newton-sec per meter
Newton-sec² per meter
The celerity (velocity) of a pressure wave in a fluid is given by (where K = Bulk modulus, and ρ = Density of the fluid)
K.ρ
K/ρ
ρ/K
None of these
The resultant upward pressure of a fluid on a floating body is equal to the weight of the fluid displaced by the body. This definition is according to
Buoyancy
Equilibrium of a floating body
Archimedes' principle
Bernoulli's theorem
When a body floating in a liquid, is displaced slightly, it oscillates about
C.G. of body
Center of pressure
Center of buoyancy
Metacentre
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
The highest efficiency is obtained with a channel of __________ section.
Circular
Square
Rectangular
Trapezoidal
In a free nappe,
The pressure below the nappe is atmospheric
The pressure below the nappe is negative
The pressure above the nappe is atmospheric
The pressure above the nappe is negative
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
The discharge through a channel of circular section will be maximum when the depth of water is __________ the diameter of the circular channel.
0.34 times
0.67 times
0.81 times
0.95 times
According to equation of continuity,
w1a1 = w2a2
w1v1 = w2v2
a1v1 = a2v2
a1/v1 = a2/v2
Piezometer is used to measure
Pressure in pipe, channels etc.
Atmospheric pressure
Very low pressures
Difference of pressure between two points
If the atmospheric pressure on the surface of an oil tank (sp. gr. 0.8) is 0.2 kg/cm, the pressure at a depth of 50 m below the oil surface will be
2 meters of water column
3 meters of water column
5 meters of water column
6 meters of water Column
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 unit of surface tension is
N/m
N/m2
N/m3
N-m
Which of the following instrument can be used for measuring speed of an aeroplane?
Venturimeter
Orifice plate
Pitot tube
Rotameter
The total pressure on the top of a closed cylindrical vessel completely filled up with a liquid is
Directly proportional to (radius)2
Inversely proportional to (radius)2
Directly proportional to (radius)4
Inversely proportional to (radius)4
Uniform flow occurs when
The flow is steady
The flow is streamline
Size and shape of the cross section in a particular length remain constant
Size and cross section change uniformly along length
When a liquid is flowing through a pipe, the velocity of the liquid is
Maximum at the centre and minimum near the walls
Minimum at the centre and maximum near the walls
Zero at the centre and maximum near the walls
Maximum at the centre and zero near the walls
An error of 1% in measuring head over the apex of the notch (H) will produce an error of _________ in discharge over a triangular notch.
1 %
1.5 %
2 %
2.5 %
The most economical section of a trapezoidal channel is one which has hydraulic mean depth equal to
1/2 × depth
1/2 × breadth
1/2 × sloping side
1/4 × (depth + breadth)
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
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