A jet of water discharging from a 40 mm diameter orifice has a diameter of 32 mm at its vena contracta. The coefficient of contraction is
0.46
0.64
0.78
0.87
Correct Answer :
B. 0.64
Related Questions
The discharge over a rectangular notch is
Inversely proportional to H3/2
Directly proportional to H3/2
Inversely proportional to H5/2
Directly proportional to H5/2
Surface energy per unit area of a surface is numerically equal to
Atmospheric pressure
Surface tension
Force of adhesion
Force of cohesion
The torque required to overcome viscous resistance of a footstep bearing is (where μ = Viscosity of the oil, N = Speed of the shaft, R = Radius of the shaft, and t = Thickness of the oil film)
μπ²NR/60t
μπ²NR²/60t
μπ²NR³/60t
μπ²NR⁴/60t
The power transmitted through the pipe is maximum when the head lost due to friction is equal to
One-fourth of the total supply head
One-third of the total supply head
One-half of the total supply head
Two-third of the total supply head
Manometer is used to measure
Pressure in pipes, channels etc.
Atmospheric pressure
Very low pressure
Difference of pressure between two points
When the Mach number is less than unity, the flow is called
Sub-sonic flow
Sonic flow
Super-sonic flow
Hyper-sonic flow
When the coefficient of discharge (Cd) is 0.623, then the general equation for discharge over a rectangular weir is
1.84 (L - 0.1nH)H3/2
1.84 (L - nH)H2
1.84 (L - 0.1nH)H5/2
1.84 (L - nH)H3
Which of the following is an example of laminar flow?
Underground flow
Flow past tiny bodies
Flow of oil in measuring instruments
All of these
When a tube of smaller diameter is dipped in water, the water rises in the tube with an upward __________ surface.
Concave
Convex
Plane
None of these
The critical depth for a channel is given by (where q = Unit discharge (discharge per unit width) through the channel)
(q/g)1/2
(q²/g)1/3
(q³/g)1/4
(q⁴/g)1/5
When the Venturimeter is inclined, then for a given flow it will show __________ reading.
Same
More
Less
None of these
A body floats in stable equilibrium
When its meatcentric height is zero
When the metacentre is above C.G.
When its e.g. is below its center of buoyancy
Metacentre has nothing to do with position of e.g. for determining stability
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
The units of dynamic or absolute viscosity are
Metres² per sec
kg sec/meter
Newton-sec per meter
Newton-sec² per meter
The resultant upward pressure of the fluid on an immersed body due to its tendency to uplift the submerged body is called
Up-thrust
Reaction
Buoyancy
Metacentre
Uniform flow 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 pleasure
The pressure in the air space above an oil (sp. gr. 0.8) surface in a tank is 0.1 kg/cm. The pressure at 2.5 m below the oil surface will be
2 metres of water column
3 metres of water column
3.5 metres of water column
4 m of water column
The length AB of a pipe ABC in which the liquid is flowing has diameter (d1) and is suddenly enlarged to diameter (d2) at B which is constant for the length BC. The loss of head due to sudden enlargement is
(v₁ - v₂)²/g
(v₁² - v₂²)/g
(v₁ - v₂)²/2g
(v₁² - v₂²)/2g
Pitot tube is used for measurement of
Pressure
Flow
Velocity
Discharge
Gauge pressure at a point is equal to the absolute pressure __________ the atmospheric pressure.
Plus
Minus
Divide
Multiply
When the Mach number is between __________ the flow is called super-sonic flow.
1 and 2.5
2.5 and 4
4 and 6
1 and 6
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
Dynamic viscosity of most of the gases with rise in temperature
Increases
Decreases
Remain unaffected
Unpredictable
A manometer is used to measure
Low pressure
Moderate pressure
High pressure
Atmospheric pressure
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
The depth of the centre of pressure on a vertical rectangular gate 8 m wide and 6 m high, when the water surface coincides with the top of the gate, is
2.4 m
3.0 m
4.0 m
5.0 m
A hemispherical tank of radius (R) has an orifice of cross-sectional area (a) at its bottom and is full of liquid. The time required to empty the tank completely is
14π R1/2/15Cd × a √(2g)
14π R3/2/15Cd × a √(2g)
14π R5/2/15Cd × a √(2g)
14π R7/2/15Cd × a √(2g)
When an internal mouthpiece is running free, the discharge through the mouthpiece is: (where a = Area of mouthpiece, and H = Height of liquid above the mouthpiece)
0.5 a. √2gH
0.707 a. √2gH
0.855 a. √2gH
a. √2gH
If mercury in a barometer is replaced by water, the height of 3.75 cm of mercury will be following cm of water
51 cm
50 cm
52 cm
52.2 cm
When a body is immersed wholly or partially in a liquid, it is lifted up by a force equal to the weight of liquid displaced by the body. This statement is called
Pascal's law
Archimedess principle
Principle of floatation
Bernoulli's theorem