# Multiple choice question for engineering

## Set 1

1. The formation of vapour cavities is called _____

a) Static pressure drop

b) Cavitation

c) Isentropic expansion

d) Emulsion

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2. What is the degree of reaction denoted as?

a) D

b) R

c) r

d) d

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3. Voids are created due to ______

a) Reaction ratio

b) Pressure ratio

c) Liquid free layers

d) Volumetric layers

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4. Cavitation usually occurs due to the changes in ________

a) Pressure

b) Temperature

c) Volume

d) Heat

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5. Degree of reactions are most commonly used in ________

a) Turbomachinery

b) Pressure drag

c) Aerodynamics

d) Automobiles

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6. At high pressure, the voids can generate ______

a) Drag force

b) Mass density

c) Shock waves

d) Flow speed

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7. Voids that implode near metal surface develops a_______

a) Drag force

b) Cyclic stress

c) Shock waves

d) Flow speed

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8. Internal cavitation occurs due to __________

a) Drag force

b) Cyclic stress

c) Shock waves

d) Flow speed

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9. Non- inertial cavitation is the one in which a bubble of fluid is forced to oscillate.

a) True

b) False

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10. The efficiency of the vane is given by _________

a) 1-V_{2}^{2}/ V_{1}^{2}

b) 1-(V_{2}^{2}/ V_{1}^{2})

c) V_{2}^{2}/ V_{1}^{2}

d) 1- V_{1}^{2}

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_{2}

^{2}/ V

_{1}

^{2}).

11. The velocities of the blade angles can be found out using ________

a) Mach number

b) Froude’s number

c) Velocity triangles

d) Reynolds number

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12. Which among the following velocities cannot be found using the velocity triangle?

a) Tangential

b) Whirl

c) Relative

d) Parabolic

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13. Hydrodynamic cavitation is due to the process of _________

a) Vaporisation

b) Sedimentation

c) Filtration

d) Excavation

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14. The process of bubble generation leads to __________

a) High temperatures

b) High pressures

c) High energy densities

d) High volumetric ratio

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15. Super cavitation is the use of cavitation effect to create a bubble of steam inside a liquid.

a) True

b) False

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## Set 2

1. _____________ is defined as ratio between power delivered to runner and power supplied at inlet of turbine.

a) Mechanical efficiency

b) Volumetric efficiency

c) Hydraulic efficiency

d) Overall efficiency

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2. Which among the following which is not an efficiency of turbine?

a) Mechanical efficiency

b) Volumetric efficiency

c) Hydraulic efficiency

d) Electrical efficiency

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3. The ratio of power at the shaft of turbine and power delivered by water to runner is known as?

a) Mechanical efficiency

b) Volumetric efficiency

c) Hydraulic efficiency

d) Overall efficiency

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4. The product of mechanical efficiency and hydraulic efficiency is known as?

a) Mechanical efficiency

b) Volumetric efficiency

c) Hydraulic efficiency

d) Overall efficiency

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5. Among the following which turbine has highest efficiency?

a) Kaplan turbine

b) Francis turbine

c) Pelton turbine

d) Propeller turbine

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6. _____________ is ratio of volume of water actually striking the runner and volume of water supplied to turbine?

a) Mechanical efficiency

b) Volumetric efficiency

c) Hydraulic efficiency

d) Overall efficiency

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7. In the expression for overall efficiency of turbine, which is p/(k*g*q*h), where “k” is known as

a) Density of liquid

b) Specific density of liquid

c) Volume of liquid

d) Specific gravity of liquid

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8. The expression for maximum hydraulic efficiency of pelton turbine is given by?

a) (1+cos k)/2 where k is outlet blade angle

b) (2+cos k)/2 where k is outlet blade angle

c) (3+cos k)/2 where k is outlet blade angle

d) (4+cos k)/2 where k is outlet blade angle

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9. To obtain maximum hydraulic efficiency of pelton turbine, blade velocity should be ___________ Times the inlet velocity of jet.

a) Half

b) One quarter

c) Twice

d) Thrice

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10. Among the following which turbine has least efficiency?

a) Pelton turbine

b) Kaplan turbine

c) Francis turbine

d) Propeller turbine

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11. The ratio of volume available at shaft of turbine and power supplied at the inlet of the turbine

a) Mechanical efficiency

b) Volumetric efficiency

c) Hydraulic efficiency

d) Overall efficiency

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## Set 3

1. The efficiency of the draft tube depends on the ______

a) Heat

b) Pressure

c) Temperature

d) Pressure and temperature

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2. Draft tubes have _________ shafts

a) Horizontal

b) Vertical

c) Circular

d) Cross sectional

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3. Draft tubes are situated at the outlet in____________

a) Pelton

b) Reaction

c) Kaplan

d) Francis

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4. Efficiency of a draft tube is directly proportional to its __________

a) Temperature

b) Pressure

c) Velocity

d) Density

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5. Z is a draft tube is _______

a) Temperature difference

b) Pressure drop

c) Kinetic energy difference

d) Datum head

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6. Draft tube operates at ______

a) Same efficiency

b) Different efficiency

c) Turbine

d) Pump

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7. The draft tube is an ________

a) Interior tube

b) Exterior tube

c) Tank depth alternator

d) Nozzle tube

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8. What type of pressure does the draft tube depend upon?

a) Gauge pressure

b) Atm pressure

c) Normal pressure

d) Normal and Atm pressure

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9. Gauge pressure of the draft tube is denoted by _____

a) P

b) h

c) z

d) x

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10. Draft tube allows turbine to be placed below the tail race.

a) True

b) False

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## Set 4

1. Which of the following efficiencies for Francis Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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2. Which of the following efficiencies for Francis Turbine is described as the ratio between total quantity of water over runner blades to total quantity of water supplied to turbine?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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3. Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft of the turbine to the power produced by the runner?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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4. Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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5. The whirl velocity at inlet of Francis turbine is given to be 20 m/s. The blade velocity is given as 35 m/s. What is the hydraulic efficiency for a head of 100 m?

a) 80%

b) 90%

c) 70%

d) 98%

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6. The desired hydraulic efficiency of a turbine is 80% at a whirl velocity of 20 m/s and a head of 100 m. What should be the blade velocity of the turbine at inlet in m/s?

a) 40

b) 60

c) 80

d) 25

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7. The input water power of the Francis turbine is 1.25 times the runner power. What would be the hydraulic efficiency of the turbine (in %)?

a) 60

b) 70

c) 80

d) 90

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8. The volume flow rate into a Francis turbine is Q m3/s. 0.25Q m3/s volume of water do not flow over the runner blades. What is the mechanical efficiency of the turbine (in %)?

a) 65

b) 75

c) 80

d) Mechanical efficiency cannot be found out from the given information

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9. The volumetric efficiency of a Francis turbine is given to be 90%. If the volume flow rate through the turbine is 25 m^{3}/s. What is the flow rate of water over the runner blades (in m^{3}/s)?

a) 20

b) 25

c) 22.5

d) 21.5

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^{3}/s.

10. The volumetric efficiency of a given turbine is 80%. If volume flow rate of water in given to be 30 m^{3}/s, find the volume of water (m^{3}) NOT flowing over the runner blades per second?

a) 5

b) 6

c) 10

d) 12

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^{3}/s. The volume of water NOT flowing over the runner blades would then be 30 – 24 = 6 m

^{3}/s.

11. The power available at the shaft of a Francis turbine is 1 MW. The volume flow rate of water in 25 m^{3}/s, whirl velocity at inlet is 10 m/s and blade velocity is 5 m/s. Find the mechanical efficiency (in %)?

a) 65

b) 75

c) 80

d) 90

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12. The whirl velocity at inlet is 15 m/s and blade velocity is 10 m/s. The volume flow rate of water in 20 m^{3}/s. Find the power output available at the shaft if the mechanical efficiency is 95% (in MW)?

a) 2.85

b) 3.075

c) 6.55

d) 0.285

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_{w1u1}. Substituting the given values into this equation, we get shaft power = 2.85 MW.

13. The power output of the shaft is 5 MW. The volume flow rate of water in 10 m^{3}/s at an available head of 60 m. Find the overall efficiency of the turbine in % (g = 10 m/s^{2})?

a) 80

b) 82.5

c) 83.3

d) 85

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14. The volume flow rate of water in 10 m^{3}/s at an available head of 60 m (g = 10 m/s^{3}). Find the shaft power (in MW) if the overall efficiency of the turbine is 90%.

a) 54

b) 5.4

c) 540

d) 0.54

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15. The hydraulic efficiency of a Francis turbine is 90%, the mechanical efficiency is 95% and the volumetric efficiency is assumed to be 100%. Fine the overall efficiency (in %)?

a) 80

b) 85.5

c) 87.5

d) 83.3

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## Set 5

1. For a Kaplan turbine, the whirl velocity at inlet of the turbine is given to be 18 m/s. The blade velocity is given as 25 m/s. What is the hydraulic efficiency for a head of 50 m. Take g = 10 m/s^{2}?

a) 80%

b) 90%

c) 70%

d) 98%

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_{w1.u1}/ gH. Substituting the values of the given parameters in the equation, we get hydraulic efficiency = 90%.

2. Which of the following efficiencies for Kaplan Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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3. The desired hydraulic efficiency of a Kaplan turbine is 98% at a whirl velocity of 20 m/s and a head of 60 m. What should be the blade velocity of the turbine at inlet in m/s? Take g = 10 m/s_{2}.

a) 40

b) 60

c) 80

d) 30

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_{w1.u1}/ gH. Substituting the values of the given parameters in the equation, we get blade velocity at the inlet as 29.4 m/s which can be roughly approximated to 30 m/s.

4. It is given that the input water power of the Kaplan turbine is 1.10 times the runner power. What would be the hydraulic efficiency of the turbine (in %)?

a) 60.61

b) 70.71

c) 80.81

d) 90.91

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5. Which of the following efficiencies for Kaplan Turbine is described as the ratio between total quantity of water over runner blades to total quantity of water supplied to turbine?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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6. The volume flow rate into a Kaplan turbine is Q m^{3}/s. 0.10Q m^{3}/s volume of water do not flow over the runner blades. What further information is required to find the volumetric efficiency (numerical value) of the Kaplan turbine?

a) The numerical value of Q

b) The available head of the turbine

c) The RPM or the blade velocity of the turbine

d) No further information is required

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7. A student reports the volumetric efficiency of a Kaplan turbine to be 95%. If he measures the volume flow rate through the turbine is 40 m^{3}/s. What is the flow rate of water over the runner blades (in m^{3}/s)?

a) 38

b) 40

c) 42.11

d) 45

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^{3}/s, the volume of water over runner blades = 0.95*40 = 38 m

^{3}/s.

8. In a Kaplan turbine experiment, the volumetric efficiency of a given turbine is 91%. If volume flow rate of water in given to be 35 m^{3}/s, find the volume of water (m^{3}) NOT flowing over the runner blades per second?

a) 4.05

b) 3.15

c) 3.30

d) 2.55

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^{3}/s. The volume of water NOT flowing over the runner blades would then be 35 – 31.85 = 3.15 m

^{3}/s.

9. Which of the following efficiencies for Kaplan Turbine is defined as the ratio between the power available at the shaft of the turbine to the power produced by the runner?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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10. The power available at the shaft of a Kaplan turbine is 0.75 MW. The volume flow rate of water in 15 m^{3}/s, whirl velocity at inlet is 12 m/s and blade velocity is 5 m/s. Find the mechanical efficiency (in %)?

a) 66.66

b) 75.00

c) 83.33

d) 91.33

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_{m}= shaft power / ρQVw1u1. Substituting the given values into this equation, we get mechanical efficiency = 83.33%.

11. The whirl velocity at inlet of a Kaplan turbine is 7.5 m/s and blade velocity is 5 m/s. The volume flow rate of water in 20 m3/s. Find the power output available at the shaft if the mechanical efficiency is 93% (in MW)?

a) 0.831

b) 0.697

c) 1.362

d) 0.298

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12. In a Kaplan Turbine experimental setup, the power output of the shaft is 4.325 MW. The volume flow rate of water in 15 m^{3}/s at an available head of 50 m. Find the overall efficiency of the turbine in % (g = 10 m/s^{2})?

a) 57.66

b) 83.63

c) 81.33

d) 79.95

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13. The hydraulic efficiency of a Kaplan turbine is 95%, the mechanical efficiency is 93% and the volumetric efficiency is assumed to be 100%. Fine the overall efficiency (in %)?

a) 80.05

b) 93.15

c) 87.55

d) 88.35

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14. Which of the following efficiencies for Kaplan Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet?

a) Hydraulic efficiency

b) Volumetric efficiency

c) Mechanical efficiency

d) Overall efficiency

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15. In Kaplan turbine apparatus, the volume flow rate of water in 15 m^{3}/s at an available head of 55 m (g = 10 m/s^{2}). Find the shaft power (in MW) if the overall efficiency of the turbine is 95%.

a) 78.3

b) 7.83

c) 783

d) 0.783