Fluid Power Actuators multiple choice questions

 Fluid Power Actuators

1. What is the advantage of using a single acting cylinder?
a) high cost and reliable
b) honing inside the inner surface of pump is not required
c) piston seals are not required
d) all the above
Answer: piston seals are not required
2. What is the function of electric actuator?
a) converts electrical energy into mechanical torque
b) converts mechanical torque into electrical energy
c) converts mechanical energy into mechanical torque
d) none of the above
Answer: converts electrical energy into mechanical torque
3. Match the following group 1 items with group 2 items and select the correct option.
1. Radial motor _____________ A. Swash plate
2. Axial motor ______________ B. Crank shaft motor
3. Orbit ____________________ C. Vane motor
4. Low torque motor ________ D. Geroller motor
a) 1-B, 2-A, 3-D, 4-C
b)  1-A, 2-C, 3-B, 4-D
c)  1-C, 2- A, 3-B, 4-D
d) 1-B, 2-D, 3-A, 4-C
Answer: 1-B, 2-A, 3-D, 4-C
4. Which of the following is a hydraulic cylinder based on construction?
a) single acting cylinder
b) double acting cylinder
c) welded design cylinder
d) all the above
Answer: welded design cylinder
5. Which energy is converted into mechanical energy by the hydraulic cylinders?
a) hydrostatic energy
b) hydrodynamic energy
c) electrical energy
d) none of the above
Answer: hydrostatic energy
6. Why are hydraulic cylinders cushioned?
a) cushioning decelerates the piston of a cylinder
b) stress and vibrations can be reduced
c) both a and b
d) none of the above
Answer: both a and b
7. In single acting hydraulic cylinders, the piston comes back to its original position due to
a) spring force
b) self-weight
c) momentum of a flywheel
d) all the above
Answer: all the above
8. Which of the following statements is true?
a) Tie-rod cylinders are used in applications having working pressure of 70 bar
b) Welded type cylinders are used in systems having working pressure more than 70 bar
c) Tie-rod cylinders can be used in systems having working pressure more than 70 bar
d) All the above
Answer: All the above
9. Which of these actions does a hydraulic cylinder perform?
a) pushing
b) lifting
c) both a and b
d) none of the above
Answer: both a and b
10. Which type of motion is transmitted by hydraulic actuators?
a) linear motion
b) rotary motion
c) both a and b
d) none of the above
Answer: both a and b
11. Leakage in welded type of hydraulic cylinder is prevented by
a) wiper in gland cover
b) rod seal in end cover
c) rod seal in gland cover
d) both b and c
Answer: rod seal in gland cover
12. Double acting cylinder can be used as a single acting cylinder
a) True
b) False
Answer: True
13. Which of the following is a hydraulic cylinder based on application?
a) welded
b) bolted
c) ram
d) all the above
Answer: ram
14. Which type of hydraulic cylinder has one piston connected to piston rod extended on both the sides of the cylinder?
a) telescopic cylinder
b) tandem cylinder
c) both a and b
d) none of the above
Answer: tandem cylinder
15. When does expansion of spring and retraction of cylinder take place in spring type single acting cylinder?
a) oil pressure exerted is less than spring compression pressure
b) oil pressure exerted is more than spring compression pressure
c) oil pressure exerted and spring compression pressure are same
d) none of the above
Answer: oil pressure exerted is less than spring compression pressure
16. In a telescopic cylinder, as the number of stages increase
a) diameter of piston rod also increases
b) diameter of piston rod decreases
c) diameter of the piston rod remains the same
d) none of the above
Answer: diameter of piston rod decreases
17. Which factor decides the working pressure of a hydraulic cylinder?
a) diameter of circular flange
b) bore diameter of cylinder
c) stroke length
d) all the above
Answer: bore diameter of cylinder
18. Which of the following statements are true?
1. the length of two stage telescopic cylinder is more than a standard cylinder
2. the length of two stage telescopic cylinder is less than a standard cylinder
3. telescopic cylinder is single acting
4. telescopic cylinder is double acting
a) 1 and 3
b) 2 and 3
c) 2, 3 and 4
d)  1, 3 and 4
Answer: 2, 3 and 4
19. Which of the following statements is true for standard hydraulic cylinder and a telescopic cylinder?
a) telescopic and standard cylinders give same stroke length
b) telescopic cylinders give lesser stroke length than standard cylinder
c) telescopic cylinders give greater stroke length than standard cylinder
d) none of the above
Answer: telescopic cylinders give greater stroke length than standard cylinder
20. Telescopic cylinders have
a) only two stage units
b) only three stage units
c) two or three stage units
d) multistage units
Answer: multistage units
21. What is the function of hydraulic motor?
1. hydraulic motor converts hydraulic oil under pressure into torque and angular displacement
2. hydraulic motor converts hydraulic oil under pressure into force and linear displacement
3. hydraulic motor converts hydraulic energy into mechanical energy
4. hydraulic motor converts mechanical energy into hydraulic energy
a) 1 and 4
b) 1 and 3
c) 2 and 3
d) 2 and 4
Answer: 1 and 3
22. Which factor is considered while selecting the diameter of piston rod in hydraulic cylinder?
a) bore diameter
b) length of stroke
c)  load
d) all the above
Answer: all the above
23. Which of the following is used for mounting purpose in hydraulic cylinders?
a) Female clevis
b) Circular flange
c) Trunnion
d) All the above
Answer: All the above
24. Which motor causes heavy loads due to its usage in order to move at constant lower speeds?
a) Low-torque high-speed motors
b) High-torque low-speed motors
c)  both a and b
d) none of the above
Answer: High-torque low-speed motors
25. In adjustable type of cushioning
a) piston rod can be moved at very slow speed
b) piston rod can be moved at increased speed
c) both a and b
d) none of the above
Answer: both a and b
26. Which of the following is a type of cushioning in hydraulic cylinders?
a) trunnion cushioning
b) adjustable cushioning
c) clevis cushioning
d) none of the above
Answer: adjustable cushioning
27. Which end of the hydraulic cylinder, the male clevis is mounted on?
a) cap end
b) rod end
c) both a and b
d) none of the above
Answer: both a and b
28. Low-torque high-speed motors are used in
a) cranes
b) winches
c) fans
d) all the above
Answer: fans
29. How does cushioning affect the speed of the piston when the cylinder is cushioned at extreme end?
a) cushioning decreases the speed of piston near the extreme ends of the cylinder
b) cushioning increases the speed of piston near the extreme ends of the cylinder
c) cushioning increases the speed of piston at the beginning of the stroke in the cylinder
d) cushioning decreases the speed of piston at the beginning of the stroke in the cylinder
Answer: cushioning decreases the speed of piston near the extreme ends of the cylinder
30. Cam lobe hydraulic motor is a type of
a) axial hydraulic motor
b) orbit hydraulic motor
c) gear hydraulic motor
d) radial hydraulic motor
Answer: radial hydraulic motor
31. Motors used in high speed applications have
a) high torque with high speed
b) low torque with high speed
c) high torque with low speed
d) none of the above
Answer: low torque with high speed
32. Which of the following is a type of low-torque high-speed motor?
a) radial piston motors
b) axial piston motors
c) bent axis motor
d) gear motor
Answer: gear motor
33. What causes reduction in speed of the piston rod when the hydraulic cylinder is cushioned?
a) oil flow through small space
b) back pressure created in the system
c) both a and b
d) none of the above
Answer: both a and b
34. What happens when supply of oil to a single acting cylinder is stopped?
a) no pressure is exerted on the system
b) more pressure is exerted on the piston
c) less pressure is exerted on the piston
d) none of the above
Answer: less pressure is exerted on the piston
35. Which type of system uses ‘oil under pressure’ means for power transmission?
a) Fluid power system
b) Hydraulic system
c) Pneumatic system
d) Stepper motors
Answer: Hydraulic system

 Fluid Flow

1. In laminar flow fluid particles flow along a streamline.
a) True
b) False
Answer: True
2. Which of the following statements is true regarding one and two-dimensional flows?
a) Flow in a pipe is always taken as one-dimensional flow
b) Flow in a pipe is always taken as two-dimensional flow
c) Flow in a pipe is taken as one-dimensional flow when average flow parameters are considered
d) Flow in a pipe is taken as two-dimensional flow when average flow parameters are considered
Answer: Flow in a pipe is taken as one-dimensional flow when average flow parameters are considered
3. Eddies formed in the turbulent flow are major cause of the energy loss in the turbulent flow.
a) True
b) False
Answer: True
4. Uniform flow is defined as the type of flow in which acceleration is zero i.e velocity is constant.
a) True
b) False
Answer: False
5. Which of the following is true?
a) Flow is rotational inside the boundary layer and irrotational outside
b) Flow is irrotational inside the boundary layer and rotational outside
c) Flow is rotational both inside and outside of the boundary layer
d) Flow is irrotational both inside and outside of the boundary layer
Answer: Flow is rotational inside the boundary layer and irrotational outside
6. For compressible flow specific gravity remains same.
a) True
b) False
Answer: False
7.In unsteady flow, the flow parameters change with respect to position.
a) True
b) False
Answer: False
8. If the velocity is function of two space coordinates along with time then fluid flow is three dimensional in nature.
a) True
b) False
Answer: True
9. Which method is used exclusively in fluid mechanics?
a) Lagrangian method
b) Eulerian method
c) Both Lagrangian and Eulerian methods
d) Neither Lagrangian nor Eulerian method
Answer: Eulerian method
10. What type of flow can be taken for granted in a pipe of a uniform cross-section?
a) steady
b) unsteady
c) uniform
d) non-uniform
Answer: uniform
11. “The velocity of entrance and exit through a nozzle remains the same.” Is this ever possible?
a) only if the flow is compressible
b) only if the flow is laminar
c) only if the flow is rotational
d) never possible
Answer: only if the flow is compressible
12. Can the flow inside a nozzle be steady and uniform?
a) yes
b) never
c) it can be steady but never uniform
d) it can be uniform but never steady
Answer: it can be steady but never uniform
13. Three flows named as 1,2 and 3 are observed. The Reynold’s number for the three are 100, 1000 and 10000. Which of the flows will be laminar?
a) only 1
b) only 1 and 2
c) 1, 2 and 3
d) only 3
Answer: only 1 and 2
14. Which of the following is true?
a) Flow is laminar inside the boundary layer and turbulent outside
b) Flow is turbulent inside the boundary layer and laminar outside
c) Flow is laminar both inside and outside of the boundary layer
d) Flow is turbulent both inside and outside of the boundary layer
Answer: Flow is laminar inside the boundary layer and turbulent outside
15. Which method is most commonly used in fluid mechanics for analysis?
a) Langragian method
b) Eulerian Method
c) Control volume analysis
d) None of the mentioned
Answer: Eulerian Method
16. In which method of fluid flow analysis do we describe the motion parameters at a point?
a) Langragian method
b) Eulerian Method
c) Control volume analysis
d) None of the mentioned
Answer: Eulerian Method
17. When the flow particles flow in zigzag manner and rotate about their own axis it is what type of flow?
a) Turbulent flow
b) Irrotational flow
c) Rotational flow
d) None of the mentioned
Answer: None of the mentioned
18. What is unit for flow rate for gases?
a) m3/s
b) litres/s
c) cm3/s
d) kgf/s
Answer: kgf/s


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