Performance Characteristics of Centrifugal Pump

In a centrifugal pump, the regulating valve is provided on the
Which type of vanes is suitable for high speed runners?
The efficiency of a pump is generally less than that of a turbine.(Say true or false)
The volute casing of a centrifugal pump has which of the following functions?
1.Eliminating loss of head due to change in velocity after exit from Impeller
2.Directs the flow towards the delivery pipe
3.Converts a part of the velocity head to pressure head
4.Gives a constant velocity of flow
Which one of the following is the correct statement for a given centrifugal pump?