  # Turbo Machines MCQs with answers - Part 3

Q.no 1. The Francis turbine of runner diameter 0.484 m is running at 700 r.p.m.. Determine velocity of wheel at inlet.
A : 17.73 m/s
B : 4.07 m/s
C : 6.56 m/s
D : 30.14 m/s

Q.no 2. The kaplan turbine runs at 65 r.p.m. and head of 5 m. Power available at the turbine shaft is 6000 kW. Determine the specific speed of the turbine.
A : 316.49
B : 188.55
C : 673.4
D : 1299.66

Q.no 3. The water jet after striking the flat plate will be deflected at an angle of
A : 110 degrees
B : 60 degrees
C : 90 degrees
D : None of these

Q.no 4. The power developed by a turbine is (where H = Head of water under which the turbine is working)
A : Directly proportional to H1/2
B : Inversely proportional to H1/2
C : Directly proportional to H3/2
D : Inversely proportional to H3/2

Answer:-C : Directly proportional to H3/2

Q.no 5. A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit discharge of wheel is
A : 0.25 m3/s
B : 0.5 m3/s
C : 1.5 m3/s
D : 2 m3/s

Q.no 6. workdone per second in case of jet of water striking on a moving Inclined plate is ________
A : Fx .u/2
B : Fx.u
C : Fx. V
D : zero

Q.no 7. The francis turbine runs at 794 r.p.m. and head of 50.4 m. Power available at the turbine shaft is 293.13 kW. Determine the specific speed of the turbine.
A : 28.34
B : 22.27
C : 101.23
D : 242.95

Q.no 8. A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?
A : Pelton wheel with one nozzle
B : Pelton wheel with two or more nozzles
C : Kaplan turbine
D : Francis turbine

Answer:-A : Pelton wheel with one nozzle

Q.no 9. 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

Q.no 10. Radial length of Pelton wheel bucket lies between____ Where d is diameter of jet
A : 2 d to 2.5 d
B : 2 d to 3 d
C : 1.5 d to 2.5 d
D : 2.5 d to 3.5 d

Answer:-B : 2 d to 3 d

Q.no 11. A Pelton wheel develops 1750 kW under a head of 100 meters while running at 200 r.p.m. and discharging 2500 liters of water per second. The unit speed of the wheel is
A : 10 r.p.m.
B : 20 r.p.m.
C : 40 r.p.m.
D : 80 r.p.m.

Q.no 12. Pelton Wheel is a
A : Impulse Turbine
B : Tangential flow turbine
D : all of the options

Q.no 13. A pelton wheel is having a mean bucket diameter of 1m and is running at 1000r.p.m.The net head on the pelton wheel is 700m.If the side clearance angle is 15◦ and discharge through nozzle is 0.1 m3/s,Find i)Power available at the nozzle.
A : 234.8 kW
B : 686.7 kW
C : 397.1 kW
D : 426.5 kW

Q.no 14. A jet of water of diameter 100 mm moving with a velocity of 30 m/s strikes a fixed curved symmetrical vane at center. The force exerted by jet of water is ________ if the jet is deflected by an angle of 120 degrees at the outlet of curved vane
A : 106.02 N
B : 1060.2 N
C : 10602.7 N
D : 106027 N

Q.no 15. The efficiency of a Pelton wheel working under constant head ________ with the increase in power.
A : Remain same
B : Increases
C : Decreases
D : None of these

Q.no 16. Following data is given for reaction turbine: work done = 3952 kW, Velocity of whirl at inlet = 27.184 m/s, Tangential velocity of blade= 24.3 m/s. Determine discharge of the turbine. Assume whirl velocity at outlet as zero.
A : 20.21 m3/s
B : 10.97 m3/s
C : 25.19 m3/s
D : 5.98 m3/s

Q.no 17. The reaction turbine works under head of 7.62 m. The velocity of whirl at inlet to the turbine is 18.4 m/s and blade velocity at inlet is 3.17 m/s. Determine the hydraulic efficiency of the turbine.
A : 42.77%
B : 78.02%
C : 32.76%
D : 23.400000000000002%

Q.no 18. If Hg is the gross or total head and hf is the head lost due to friction, then net or effective head (H) is given by
A : H = Hg/hf
B : H = Hg × hf
C : H = Hg + hf
D : H = Hg - hf

Answer:-D : H = Hg - hf

Q.no 19. An impulse turbine
A : is more suited for low head installations
B : always operates submerged
C : makes use of draft tube
D : operates with initial completion conversion of pressure head to velocity head

Q.no 20. Water Jet 0.0015 Sq. meter area issues from a nozzle with 15m/s velocity. It is made to impinge perpendicular onto a plate that moves away with the velocity of 5 m/s. The force on the plate due to this impact is
A : 150 N
B : 1470 N
C : 340 N
D : 900 N