Related Mcqs:

1. Net positive suction head (NPSH) of a centrifugal pump must be____________________?

   A. Greater than the vapour pressure of the liquid
   B. Less than the vapour pressure of the liquid
   C. Equal to the vapour pressure of the liquid
   D. Less than barometric pressure

2. In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure ______________ the vapor pressure of the liquid at the suction temperature?

   A. Lower than
   B. Higher than
   C. Equal to
   D. None of these

3. A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit E. to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062 ?

   A. 10 m
   B. 11 m
   C. 11.8 m
   D. 30 m

4. Cavitation occurs in a centrifugal pump when the suction pressure is________________?

   A. Less than the vapour pressure of the liquid at that temperature
   B. Greater than the vapour pressure of the liquid at that temperature
   C. Equal to the vapour pressure
   D. Equal to the developed head

5. The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the___________________?

   A. Static submergence
   B. Net positive suction head (NPSH)
   C. Cavitation sensitivity
   D. Priming

6. A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now_________________?

   A. Increase
   B. Decrease
   C. Remain same
   D. Data insufficient to predict

7. A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump_________________?

   A. Develops a lower head
   B. Capacity is reduced
   C. Requires more power
   D. All A., B. and C.

8. Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) ?

   A. D = 1840 H0.5/N
   B. D = 1840 N/H0.5
   C. H = 1840 D0.5/N
   D. D = 1840 H/N

9. Foot valves are provided in the suction line of a centrifugal pump to ____________________?

   A. Avoid priming, every time we start the pump
   B. Remove the contaminant present in the liquid
   C. Minimise the fluctuation in discharge
   D. Control the liquid discharge

10. Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be _____________________ ft?

    A. 40
    B. 34
    C. 8
    D. 37