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71.

The discharge through a reaction turbine

A.	remains same	B.	increases
C.	decreases

72.

The efficiency of a reaction turbine for a given head

decreases

increases

73.

The cavitation in a hydraulic machine is mainly due to

A.	low velocity	B.	high velocity
C.	low pressure	D.	high pressure

74.

The cavitation in ahydraulic machine

A.	causes noise and vibration of various parts	B.	reduces the discharge of a turbine
C.	causes sudden drop in power output and efficiency	D.	all of the above

75.

The cavitation in reaction turbines is avoided, to a great extent by

A.	installing the turbine below the tail race level	B.	using stainless steel runner of the turbine
C.	providing highly polished blades to the runner	D.	all of the above

76.

The specific speed of a hydraulic turbine depends upon

A.	speed and power developed	B.	discharge and power developed
C.	speed and head of water	D.	speed, power developed and head of water

77.

Which of the following statement is wrong?

A.	The reaction turbines are used for low head and high discharge.	B.	The angle of taper on draft tube is less than 8?
C.	An impulse turbine is generally fitted slightly above the tail race.	D.	A Francis turbine is an impulse turbine.

78.

The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which

A.	delivers unit discharge under unit head	B.	delivers unit discharge under unit speed
C.	develops unit power under unit head	D.	develops unit power under unit speed

79.

In a centrifugal pump, the water enters the impeller

axially

radially

80.

The action of a centrifugal pump is that of a reversed reaction turbine.

Correct

Incorrect