Multiple Choice Questions and Answers (MCQs) on Hydraulics & Fluid Machineries
01. Low specific speed of a pump implies it is
(A) Centrifugal pump
(B) Mixed flow pump
(C) Axial flow pump
(D) None of the above
Answer: Option A
02. Head developed by a centrifugal pump is
(A) Proportional to diameter of impeller
(B) Proportional to speed of impeller
(C) Proportional to diameter and speed of impeller
(D) None of the above
Answer: Option C
03. In centrifugal pumps, maximum efficiency is obtained when the blades are
(A) Straight
(B) Bent forward
(C) Bent backward
(D) Radial
Answer: Option C
04. A double overhung Pelton wheel has
(A) Two jets
(B) Two runners
(C) Four jets
(D) Four runners
Answer: Option B
05. Medium specific speed of a pump implies it is
(A) Centrifugal pump
(B) Mixed flow pump
(C) Axial flow pump
(D) Any one of the above
Answer: Option B
06. If the ratios of all the corresponding linear dimensions are equal, then the model and the prototype are said to have
(A) Geometric similarity
(B) Kinematic similarity
(C) Dynamic similarity
(D) None of these
Answer: Option A
07. The optimum value of vane exit angle for a centrifugal pump impeller is
(A) 10-15°
(B) 20-25°
(C) 30-40°
(D) 50-60°
Answer: Option B
08. Which of the following pump is suitable for small discharge and high heads?
(A) Centrifugal pump
(B) Axial flow pump
(C) Mixed flow pump
(D) Reciprocating pump
Answer: Option D
09. For small discharge at high pressure, following pump is preferred
(A) Centrifugal
(B) Axial flow
(C) Mixed flow
(D) Reciprocating
Answer: Option D
10. A hydraulic press is a device used
(A) To store pressure energy which may be supplied to a machine later on
(B) To increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure
(C) To lift larger load by the application of a comparatively much smaller force
(D) All of the above
Answer: Option C
11. Low specific speed of turbine implies it is
(A) Propeller turbine
(B) Francis turbine
(C) Impulse turbine
(D) Any one of the above
Answer: Option C
12. The function of guide vanes in a reaction turbine is to
(A) Allow the water to enter the runner without shock
(B) Allow the water to flow over them, without forming eddies
(C) Allow the required quantity of water to enter the turbine
(D) All of the above
Answer: Option D
13. Hydraulic accumulator is used for
(A) Accumulating oil
(B) Supplying large quantities of oil for very short duration
(C) Generally high pressures to operate hydraulic machines
(D) Supplying energy when main supply fails
Answer: Option D
14. The jet ratio is defined as the ratio of the
(A) Diameter of jet to the diameter of Pelton wheel
(B) Velocity of jet to the velocity of Pelton wheel
(C) Diameter of Pelton wheel to the diameter of jet
(D) Velocity of Pelton wheel to the velocity of jet
Answer: Option C
15. Maximum impulse will be developed in hydraulic ram when
(A) Waste valve closes suddenly
(B) Supply pipe is long
(C) Supply pipe is short
(D) Ram chamber is large
Answer: Option A
16. In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by
(A) Designing new impeller
(B) Trimming the impeller size to the required size by machining
(C) Not possible
(D) Some other alterations in the impeller
Answer: Option B
17. Which of the following pump is successfully used for lifting water to the turbines?
(A) Centrifugal pump
(B) Reciprocating pump
(C) Jet pump
(D) Air lift pump
Answer: Option C
18. If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water, the horse power required will be
(A) Same
(B) 0.75 B.H.P.
(C) B.H.P./0.75
(D) 1.5 B.H.P.
Answer: Option B
19. A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is ________ of the jet velocity
(A) One-half
(B) One-third
(C) Two-third
(D) Three-fourth
Answer: Option B
20. In a centrifugal pump, the liquid enters the pump
(A) At the top
(B) At the bottom
(C) At the canter
(D) From sides
Answer: Option C
21. Kinematic similarity is said to exist between the model and the prototype, if both of them
(A) Have identical velocities
(B) Are equal in size and shape
(C) Are identical in shape, but differ only in size
(D) Have identical forces
Answer: Option A
22. For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred
(A) Centrifugal
(B) Axial flow
(C) Reciprocating
(D) Mixed flow
Answer: Option B
23. The flow ratio of Francis turbine is defined as the ratio of the
(A) Velocity of flow at inlet to the theoretical jet velocity
(B) Theoretical velocity of jet to the velocity of flow at inlet
(C) Velocity of runner at inlet to the velocity of flow at inlet
(D) None of the above
Answer: Option A
24. The maximum number of jets generally employed in impulse turbine without jet interference is
(A) 4
(B) 6
(C) 8
(D) 12
Answer: Option B
25. The specific speed (Ns) of a centrifugal pump is given by
(A) (N√Q)/H2/3
(B) (N√Q)/H3/4
(C) (N√Q)/H
(D) (N√Q)/H5/4
Answer: Option B