Fluid Mechanics

Fluid Mechanics MCQs
Fluid Mechanics Objectives

Fluid Mechanics Previous Year MCQs

Topic :- Hydraulic Machine (Pump)

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Fluid Mechanics MCQs
Fluid Mechanics Objectives

Fluid Mechanics Previous Year MCQs

Topic :- Hydraulic Machine (Pump)

Q.1. The head developed by the centrifugal pump is 40 m while operating at the speed of 750 rpm. If the rated capacity is given as 50 cumec, what is the specific speed of centrifugal pump? [SSC : JE : 2018]

a) 150

b) 300

c) 333 ✔

d) 500

Q.2. Which of the following statement is CORRECT? [SSC : JE : 2018]

a) Pumps connected in parallel are used to boost the head, whereas pump operating in series boosts the discharge.

b) Pump operating in series, boosts the head, whereas pump operating in parallel, boosts the discharge. ✔

c) Pump either in parallel or series always boost only discharge.

d) Pump either in parallel or series always boost only head.

Q.3. What is the specific speed of a centrifugal pump, which has a rated capacity of 44 cumec and a head of 36 m when operated at the speed of 725 rpm? [SSC : JE : 2018]

a) 45

b) 227

c) 327 ✔

d) 350

Q.4. The specific speed of a pump is defined as the speed of a unit of such a size that it discharges: [SSC : JE : 2015]

a) unit discharge at unit power

b) unit work at unit head loss

c) unit discharge at unit head ✔

d) unit volume at unit time

Q.5. Which one of the following statement is true for pumps operating in parallel? [PWD : 2018]

a) Discharge increase ✔

b) Discharge decrease

c) Head increase

d) Head decrease

Q.6. Which one of the following statement is true for pumps operating in series? [PWD : 2018]

a) Discharge increase

b) Discharge decrease

c) Head increase ✔

d) Head decrease

Q.7. A single speed centrifugal pump, feeding a small water supply distribution system of a block of houses, works at:- [PWD : 2018]

a) Maximum efficiency

b) Reduced efficiency ✔

c) Minimum efficiency

d) None of the above

Q.8. Which of the following pump is successfully used for lifting water to the turbine [DMRC : JE : 2017]

a) Air lift pump

b) Centrifugal pump

c) Reciprocating pump

d) Jet pump ✔

Q.9. A mono pump is also known as: [DMRC : JE : 2017]

a) Piston

b) a group of vacuum

c) Centrifugal

d) positive acting rotary ✔

Q.10. In a centrifugal pump, the liquid enters the pump: [DMRC : JE : 2017]

a) At the center

b) At the top

c) From sides

d) At the bottom ✔

Q.11. Priming is useful in a_______ pump. [DMRC : JE : 2017]

a) centrifugal ✔

b) reciprocating

c) diaphragm

d) gear

Q.12. A centrifugal pump delivers a liquid when pressure rise in impeller is equal to______[DMRC : JE : 2017]

a) kinetic head

b) velocity head

c) static head

d) manometric head ✔

Q.13. The specific speed of the pump increases with [SSC : JE : 2016]

a) increase in shaft speed

b) increase in discharge

c) decrease in gravitational acceleration

d) increase in head ✔

Q.14. The centrifugal pump should be installed above the water level in the sump such that [SSC : JE : 2016]

a) its height is not more than 1.03 m at room temperature of liquid

b) its height is not allowed to exceed 6.7 m

c) the negative pressure does not reach as low as the vapour pressure ✔

d) None of these

Q.15. In a centrifugal pump casing, the flow of water leaving the impeller is [SSC : JE : 2016]

a) Radial

b) Centrifugal

c) Rectilinear

d) Free vortex ✔

Q.16. In centrifugal pump, the inlet angle will be designed to have [MPSC : 2012]

a) relative velocity vector in radial direction

b) absolute velocity vector in radial direction ✔

c) velocity of flow to be zero

d) peripheral velocity to be zero

Q.17. Reciprocating pump belongs to which of the following types ? [MPSC : 2013]

a) Rotary pump

b) Propeller pump

c) Mixed flow pump

d) Displacement pump ✔

Q.18. If three pipes of different diameters, lengths and friction factors are connected in series, then : [MPSC : 2015]

a) f = f₁ + f₂ + f₃

b) hf₁ = hf₂ = hf₃

c) Q = Q₁ + Q₂ + Q₃

d) Q₁ = Q₂ = Q₃ ✔

Q.19. The difference between theoretical discharge and actual discharge of pump is known as : [MPSC : 2015]

a) gap of discharge

b) differential discharge

c) slip of pump ✔

d) suction gap

Q.20. Overall efficiency of a pump is obtained by which of the following equations with usual notations ? [MPSC : 2015]

a) ηₒ = ηₘₐₙ x η𝘮𝘦𝘤𝘩

b) ηₒ = ηₘₐₙ x ηₕᵧ

c) ηₒ= η𝘮𝘦𝘤𝘩 x ηₕᵧ ✔

d) ηₒ= ηᵥₒₗ x ηₘᵢₙ

Q.21. To produce a high head multistage centrifugal pumps, the impellers are connected : [MPSC : 2015]

a) in parallel

b) in series ✔

c) in parallel and in series both

d) none of the above

Q.22. During suction stroke of a reciprocating pump, the separation may take place [MPSC : 2018]

a) at the end of suction stroke

b) in the middle of suction stroke

c) at the beginning of suction stroke ✔

d) None of the above

Q.23. For a centrifugal pump, suction lift head is the [MPSC : 2017]

a) Vertical distance between the top surface of liquid level in the discharge tank and pump centre line

b) Vertical distance between free surface of liquid level in the sump and pump centre line ✔

c) Head for overcoming friction loss in the suction pipe, entry loss at entrance to the friction pipe and running fluid in the suction pipe

d) None of the above

Q.24. A graph between the pressure head in the cylinder and the distance travelled by the piston from inner dead centre for one complete revolution of crank in known as [MPSC : 2017]

a) Slip diagram

b) Crank diagram

c) Polar diagram

d) Indicator diagram ✔

Q.25. The manometer head (Hm) of a centrifugal pump is given by [MPSC : 2017]

a) Pressure head at outlet of pump - pressure head at inlet

b) Total head at inlet - total head at outlet

c) Total head at outlet - total head at inlet ✔

d) None of the above

Q.26. In hydraulic head, NPSH is used for the analysis of __________

a) Adiabatic expansion

b) Priming