12) In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by

13) If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge

14) The horse power required in above case will be

15) Low specific speed of a pump implies it is

16) The optimum value of vane exit angle for a centrifugal pump impeller is