Practice Test: Question Set - 05
1. Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of
- (A) 39.2%
- (B) 49.2%
- (C) 68.8%
- (D) 84.8%
2. Overall efficiency of a centrifugal pump is the ratio of
- (A) Energy
available at the impeller to the energy supplied to the pump by the prime mover
- (B) Actual
work-done by the pump to the energy supplied to the pump by the prime mover
- (C) Energy
supplied to the pump to the energy available at the impeller
- (D) Manometric head to the energy supplied by the impeller per kN of water
3. Which of the following pump is generally used to pump highly viscous fluid?
- (A) Centrifugal
pump
- (B) Reciprocating
pump
- (C) Air
lift pump
- (D) Screw
pump
4. High specific speed of turbine implies it is
- (A) Propeller turbine
- (B) Francis turbine
- (C) Impulse turbine
- (D) None of the above
5. In a reciprocating pump, air vessels are used to
- (A) Smoothen
the flow
- (B) Reduce
suction head
- (C) Increase
delivery head
- (D) Reduce
acceleration head
6. The specific speed of a turbine is given by the equation
- (A) N√P / H3/2
- (B) N√P / H²
- (C) N√P / H5/4
- (D) N√P / H3
7. In order to avoid cavitation in centrifugal pumps
- (A) The
suction pressure should be high
- (B) The
delivery pressure should be high
- (C) The
suction pressure should be low
- (D) The
delivery pressure should be low
8. The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as
- (A) Normal speed
- (B) Unit
speed
- (C) Specific
speed
- (D) None
of these
9. Francis turbine is best suited for
- (A) Medium head application from 24 to 180 m
- (B) Low head installation
up to 30 m
- (C) High head
installation above 180 m
- (D) All types of heads
10. Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and ηo = Overall efficiency of the pump)
- (A) (w
Hm) / (Q × Î·o)
- (B) (w
Hm Q) / ηo
- (C) (w
Q) / (Hm × Î·o)
- (D) (w
Q ηo) / Hm
11. By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. The saving in case of a double acting reciprocating pump is
- (A) 39.2%
- (B) 48.8%
- (C) 84.8%
- (D) 88.4%
12. Any change in load is adjusted by adjusting following parameter on turbine
- (A) Net head
- (B) Absolute velocity
- (C) Blade velocity
- (D) Flow
13. The maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet)
- (A) (1 + cos φ)/2
- (B) (1 - cos φ)/2
- (C) (1 + sin φ)/2
- (D) (1 - sin φ)/2
14. The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is _______ of the jet velocity,
- (A) One-fourth
- (B) One-half
- (C) Three-fourth
- (D) Double
15. A hydraulic intensifier normally consists of
- (A) Two cylinders, two rams and a storage
device
- (B) A cylinder and a ram
- (C) Two coaxial rams and
two cylinders
- (D) A cylinder, a piston,
storage tank and control valve
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