A. Its capacity varies directly as the square of speed
B. Head varies as the square of speed
C. Horsepower input varies as the square of speed
D. Head varies as the speed
Related Mcqs:
- 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. - 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 - At a constant speed of the centrifugal pump, it‟s _____________ the impeller diameter?
A. Capacity varies directly with
B. Head varies as the square of
C. Horsepower varies as the cube of
D. All A., B. and C. - The blades of a centrifugal impeller are said to be curved forward, if the ____________ of the motion of impeller blades?
A. Inlet tip of a blade curves in a direction opposite to that
B. Outlet tip of a blade curves in a direction opposite to that
C. Inlet tip of a blade is towards the direction
D. Outlet tip of a blade is towards the direction - 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 - 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 - 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. - 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 - Erosion and pits formation on the impeller of a centrifugal pump may be due to________________?
A. Cavitation
B. Low speed of impeller
C. Its operation with delivery valve closed for considerable time after starting the pump
D. Off centering of pump with motor - In case of a centrifugal pump, the theoretical head developed is dependent on the _____________ the impeller?
A. Speed of
B. Diameter of
C. Fluid velocity leaving
D. All A., B. and C.
