Fluid Mechanics and Hydraulic Machines (3141906) MCQs

MCQs of Impact of Jet and Hydraulic Turbines

Showing 11 to 20 out of 30 Questions
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11.
The hydraulic efficiency of an impulse turbine is the
(a) ratio of the actual power developed by the turbine to the energy actually supplied by the turbine
(b) ratio of the actual work available at the turbine to the energy imparted to the wheel
(c) ratio of the work done on the wheel to the energy of the jet
(d) none of the above
Answer:

Option (c)

12.
The mechanical efficiency of an impulse turbine is
(a) ratio of the actual power developed by the turbine to the energy actually supplied by the turbine
(b) ratio of the actual work available at the turbine to the energy imparted to the wheel
(c) ratio of the work done on the wheel to the energy of the jet
(d) none of the above
Answer:

Option (b)

13.
The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is …………… of the jet velocity.
(a) one-fourth
(b) one-half
(c) three-fourth
(d) double
Answer:

Option (b)

14.
The maximum hydraulic efficiency of an impulse turbine is
(a) 1+cosφ2
(b) 1-cosφ2
(c) 1+sinφ2
(d) 1-sinφ2
Answer:

Option (a)

15.
The relation between hydraulic efficiency ηh, mechanical efficiency ηm and overall efficiency ηo is
(a) ηh=ηo×ηm
(b) ηm=ηo×ηh
(c) ηo=ηh×ηm
(d) none of these
Answer:

Option (c)

16.
The overall efficiency for the Pelton wheel lies between
(a) 0.50 to 0.65
(b) 0.65 to 0.75
(c) 0.75 to 0.85
(d) 0.85 to 0.90
Answer:

Option (d)

17.
The width of the bucket for a Pelton wheel is generally …………… the diameter of jet.
(a) double
(b) three times
(c) four times
(d) five times
Answer:

Option (d)

18.
The depth of the bucket for a Pelton wheel is generally …………… the diameter of jet.
(a) equal to
(b) 1.2 times
(c) 1.8 times
(d) double
Answer:

Option (b)

19.
The jet ratio is defined as the ratio of the
(a) diameter of the jet to the diameter of Pelton wheel
(b) velocity of jet to the velocity of Pelton wheel
(c) diameter of Pelton wheel to the diameter of jet
(d) velocity of Pelton wheel to the velocity of jet
Answer:

Option (c)

20.
The function of guide vanes in a reaction turbine is to
(a) allow the water to enter the runner without shock
(b) allow the water to flow over them, without forming eddies
(c) allow the required quantity of water to enter the turbine
(d) all of the above
Answer:

Option (d)

Showing 11 to 20 out of 30 Questions
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