Hydraulic Machines Objective Questions with Answers - Set 11 - ObjectiveBooks

# Practice Test: Question Set - 11

1. The discharge of a double acting reciprocating pump is (where L = Length of stroke, A = Cross-sectional area of piston, and N = Speed of crank in r.p.m.)
(A) L.A.N
(B) 2 L.A.N
(C) (L.A.N)/60
(D) (2 L.A.N)/60

2. The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
(A) 40%
(B) 50%
(C) 60%
(D) 80%

3. A turbine pump is basically a centrifugal pump equipped additionally with
(B) Backward curved blades
(C) Vaned diffusion casing
(D) Inlet guide blades

4. The impeller of a centrifugal pump may have
(A) Volute casing
(B) Volute casing with guide blades
(C) Vortex casing
(D) Any one of these

5. The working of which of the following hydraulic units is based on Pascal's law?
(A) Air lift pump
(B) Jet pump
(C) Hydraulic coupling
(D) Hydraulic press

6. By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is
(A) 39.2%
(B) 48.8%
(C) 84.8%
(D) 88.4%

7. The power developed by a turbine is (where H = Head of water under which the turbine is working)
(A) Directly proportional to H1/2
(B) Inversely proportional to H1/2
(C) Directly proportional to H3/2
(D) Inversely proportional to H3/2

8. The force exerted (in Newton) by a jet of water impinging normally on a fixed plate is (where w = Specific weight of water in N/m3, a = Cross-sectional area of jet in m², and V = Velocity of jet in m/s)
(A) waV / 2g
(B) waV / g
(C) waV² / 2g
(D) waV² / g

9. Indicator diagram of a reciprocating pump is a graph between
(A) Flow vs. swept volume
(B) Pressure in cylinder vs. swept volume
(C) Flow vs. speed
(D) Pressure vs. speed

10. The ratio of the normal force of jet of water on a plate inclined at an angle of 30° as compared to that when the plate is normal to jet, is
(A) 1/√2
(B) 1/2
(C) 1
(D) √2

11. A hydraulic coupling belongs to the category of
(A) Power absorbing machines
(B) Power developing machines
(C) Energy transfer machines
(D) Energy generating machines

12. One horsepower is equal to
(A) 102 watts
(B) 75 watts
(C) 550 watts
(D) 735 watts

13. The hydraulic efficiency of a reaction turbine, is the ratio of
(A) Power produced by the turbine to the energy actually supplied by the turbine
(B) Actual work available at the turbine to energy imparted to the wheel
(C) Work-done on the wheel to the energy (or head of water) actually supplied to the turbine
(D) None of the above

14. A Francis turbine is used when the available head of water is
(A) 0 to 25 m
(B) 25 m to 250 m
(C) Above 250 m
(D) None of these

15. For starting an axial flow pump, its delivery valve should be
(A) Closed
(B) Open
(C) Depends on starting condition and flow desired
(D) Could be either open or closed

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