This sets of MCQ's contains objective on turbo machines with answers for preparation of your exams in part 4....
SET 1 of turbo machines mcqs
Q.no 1. The Jet of water after striking the stationary flat vertical plate will be deflected at an angle of
A : 110 degrees
B : 45 degrees
C : 90 degrees
D : None of these
Answer:-C : 90 degrees
Q.no 2. With respect to a Kaplan turbine which of the following statements is incorrect?
A : It employs large guide vane angles than is the case for a Francis turbine.
B : It is designed for flow velocity of mixed flow type.
C : It has blades of small camber to prevent separation.
D : It can adjust both guide vane and blade angles according to rate of discharge.
Answer:-B : It is designed for flow velocity of mixed flow type.
Q.no 3. Which of the following statements with respect to a reaction water turbine is incorrect:
A : The spiral casing serves to uniformly distribute water into guide blades
B : The water leaves the turbine at atmospheric pressure
C : The draft tube allows setting of the turbine above the tail race with minimum reduction of available energy
D : The guide vanes direct the flow at proper angle.
Answer:-B : The water leaves the turbine at atmospheric pressure
Q.no 4. The force exerted by a jet of water in the direction of jet on a stationary curved plate is
A : ρav2
B : ρav2 Sin2θ
C : ρav2 (1+ Cosθ)
D : ρav2 (1+ Sinθ)
Answer:-C : ρav2 (1+ Cosθ)
Q.no 5. Axial width of Pelton wheel bucket lies between _____ Where d is diameter of jet
A : 2.5 d to 3 d
B : 3 d to 3.5 d
C : 3 d to 4 d
D : 3.5 d to 4.5 d
Answer:-C : 3 d to 4 d
Q.no 6. A jet strikes a curved plate at its ______
A : Sides
B : Surface
C : Centre
D : Does not strike
Answer:-C : Centre
Q.no 7. Condition for Maximum efficiency for the force exerted by jet of water on series of vertical plates is
A : 66.67%
B : 33.33%
C : 50%
D : 100%
Answer:-C : 50%
Q.no 8. A Kaplan turbine claims which of the following advantages over a Francis turbine?
A : More compact in construction and smaller in size.
B : Partload efficiency is considerably high.
C : Low frictional losses.
D : All of the above
Answer:-D : All of the above
Q.no 9. Buckets and blades used in a turbine are used to
A : To regenerate the power
B : Switch off the turbine
C : Alter the direction of water
D : To regulate the wind speed
Answer:-C : Alter the direction of water
Q.no 10. The gross or total head of the turbine is the ………….. of the water levels at the head race and tail race.
A : Sum
B : Difference
C : Product
D : Division
Answer:-B : Difference
SET 2 of turbo machines mcqs
Q.no 11. Impulse turbine is generally fitted
A : At the level of tail race
B : Little above the tail race
C : Slightly below the tail race
D : About 2.5 m above the tail race to avoid cavitations
Answer:-B : Little above the tail race
Q.no 12. ......of a turbine is defined as the ratio of power available at the turbine shaft to the power supplied by the water jet.
A : Mechanical efficiency
B : Hydraulic efficiency
C : Overall efficiency
D : Volumetric efficiency.
Answer:-C : Overall efficiency
Q.no 13. 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:-C : Diameter of Pelton wheel to the diameter of jet
Q.no 14. A Kaplan turbine is
A : an inward flow impulse turbine
B : low head axial flow turbine
C : high head axial flow turbine
D : high head mixed flow turbine.
Answer:-B : low head axial flow turbine
Q.no 15. Hydraulic Machines fall under the category :
A : Pulverizers
B : Kinetic machinery
C : Condensers
D : Roto-dynamic machinery
Answer:-D : Roto-dynamic machinery
Q.no 16. The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is …………… of the jet velocity.
A : One-fourth
B : Half
C : Three-fourth
D : Double
Answer:-B : Half
Q.no 17. A surge tank is used to
A : prevent occurrence of hydraulic jump
B : smoothen the flow
C : relieve the pipeline of excessive pressure transients
D : avoid reversal of flow.
Answer:-C : relieve the pipeline of excessive pressure transients
Q.no 18. Which of the following draft tubes is suited particularly for helical flow?
A : Conical type draft tube.
B : Elbow type draft tube.
C : Moody’s spreading draft tube.
D : None of these.
Answer:-C : Moody’s spreading draft tube.
Q.no 19. What is the general energy equation for transfer of energy between the fluid and machine? Where,
Vw1 = Tangential component of the velocity of fluid at the entry of the rotor
Vw2 = Tangential component of the velocity of fluid at the exit of the rotor u1
A : E = ṁ (Vw1 – Vw2) x (u1 – u2)
B : E = ṁ (Vw1 – Vw2) / (u1 – u2)
C : E = ṁ (Vw1 u1 – Vw2 u2)
D : E = ṁ (Vw1 u1 – Vw2 u2)2
Answer:-C : E = ṁ (Vw1 u1 – Vw2 u2)
Q.no 20. 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 these
Answer:-C : ratio of the work done on the wheel to the energy of the jet
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