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_________________?

Related Mcqs:

1. 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

2. 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.

3. A mercury (specific gravity = 13.6) manometer connected across an orificemeter fitted in a pipe shows a manometer reading of 2 cms. If the manometer liquid is changed to carbon tetrachloride (specific gravity = 1.6), then for the same flow rate of water the new manometer reading will be _______________ cms?

   A. 17
   B. 42
   C. 84
   D. 1.8

4. Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of ______________ flow type?

   A. Axial
   B. Radial
   C. Mixed
   D. None of these

5. Specific speed of a centrifugal pump relates it with another pump having the___________________?

   A. Dynamic similarity
   B. Same efficiency
   C. Same speed
   D. Geometrical similarity

6. Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the _______________ decreases?

   A. NPSH required
   B. BHP required by the pump
   C. Head of the liquid pumped
   D. All A., B. and C.

7. Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of_________________?

   A. Powder & granular solids
   B. Liquids
   C. Low melting point semi-solids
   D. All A, B & C

8. A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke’s law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity ?

   A. Same as that of A
   B. One fourth as that of A
   C. Twice as that of A
   D. Four times as that of A

9. Centrifugal pump can’t be used to pump _____________________?

   A. Molten sodium (used as a coolant in Fast Breeder Reactor)
   B. Moderately viscous vegetable oil used in soap industry
   C. Thick molten soap at 80°C
   D. None of the above

10. 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