# Hydraulic Machines-Fluid Machineries – Set 05

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## Q1. Theoretical power required (in watts) to drive a reciprocating pump is (where w = Specific weight of liquid to be pumped in N/m3, Q = Discharge of the pump in m3/s, Hs = Suction head in meters, and Hd = Delivery head in meters)

(A) wQHs
(B) wQHd
(C) wQ (Hs – Hd)
(D) wQ (Hs + Hd)

Answer: (D) wQ (Hs + Hd)

## Q2. The flow rate in gear pump

(A) Increases with increase in pressure
(B) Decreases with increase in pressure
(C) More or less remains constant with increase in pressure
(D) Unpredictable

Answer: (C) More or less remains constant with increase in pressure

## Q3. 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

Answer: (C) Directly proportional to H3/2

## Q4. If Hg is the gross or total head and hf is the head lost due to friction, then net or effective head (H) is given by

(A) H = Hg/hf
(B) H = Hg × hf
(C) H = Hg + hf
(D) H = Hg – hf

Answer: (D) H = Hg – hf

## Q5. 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

## Q6. 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: (A) Velocity of flow at inlet to the theoretical jet velocity

## Q7. The undershot water wheels are those in which

(A) The wheel runs entirely by the weight of water
(B) The wheel runs entirely by the impulse of water
(C) The wheel runs partly by the weight of water and partly by the impulse of water
(D) None of the above

Answer: (B) The wheel runs entirely by the impulse of water

## Q8. Discharge of a centrifugal pump is (where N = Speed of the pump impeller)

(A) Directly proportional to N
(B) Inversely proportional to N
(C) Directly proportional to N²
(D) Inversely proportional to N²

Answer: (A) Directly proportional to N

## Q9. 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

## Q10. Casting of a centrifugal pump is designed so as to minimize

(A) Friction loss
(B) Cavitations
(D) Loss of kinetic energy

## Q11. The specific speed of a hydraulic turbine depends upon

(A) Speed and power developed
(B) Discharge and power developed
(C) Speed and head of water
(D) Speed, power developed and head of water

## Q12. In impulse Turbine, energy available at the inlet is in the form of

(A) Potential Energy
(B) Strain Energy
(C) Kinetic energy
(D) None of these

## Q13. Slip of a reciprocating pump is negative, when

(A) Suction pipe is short and pump is running at low speeds
(B) Delivery pipe is long and pump is running at high speeds
(C) Suction pipe is short and delivery pipe is long and the pump is running at low speeds
(D) Suction pipe is long and delivery pipe is short and the pump is running at high speeds

Answer: (D) Suction pipe is long and delivery pipe is short and the pump is running at high speeds

## Q14. The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which

(A) Delivers unit discharge under unit head
(B) Delivers unit discharge under unit speed
(C) Develops unit power under unit head
(D) Develops unit power under unit speed

(A) waV / 2g
(B) waV / g
(C) waV² / 2g
(D) waV² / g

## Q16. Manometric head, in case of a centrifugal pump, is equal to

(A) Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe
(B) Work-done per kN of water Losses within the impeller
(C) Energy per kN at outlet of impeller Energy per kN at inlet of impeller
(D) All of the above

Answer: (D) All of the above

## Q17. For small discharge at high pressure, following pump is preferred

(A) Centrifugal
(B) Axial flow
(C) Mixed flow
(D) Reciprocating

(A) 4
(B) 6
(C) 8
(D) 12

## Q19. Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between

(A) Lift and resultant force
(B) Drag and resultant force
(C) Lift and tangential force
(D) Lift and drag

Answer: (A) Lift and resultant force

## Q20. The discharge through a reaction turbine with increase in unit speed

(A) Increases
(B) Decreases
(C) Remain unaffected
(D) First increases and then decreases