Q1. A hydraulic cylinder's stroke is the:

A. Linear distance traveled by the piston/rod between end positions B. Cylinder bore diameter C. Rod circumference D. Fluid volume in the reservoir

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Stroke specifies the maximum linear travel between the retracted and extended positions.

Q2. A brake valve in a hydraulic motor circuit may be used to:

A. Measure oil level B. Control overrunning loads during deceleration C. Increase piston diameter D. Replace the motor

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: With overrunning loads, the load can drive the motor. Brake/counterbalance arrangements regulate discharge pressure and prevent uncontrolled acceleration.

Q3. A 125 mm bore cylinder has a 75 mm rod. At 10 MPa, its ideal retraction force is:

A. 65.45 kN B. 44.18 kN C. 78.54 kN D. 98.17 kN

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: Annular area = π/4(0.125²−0.075²) = 0.007854 m². Therefore F = pA = 10×10⁶×0.007854 = 78.54 kN.

Q4. A rodless cylinder is advantageous when:

A. The actuator must rotate continuously B. Only manual operation is allowed C. The fluid pressure is zero D. A long stroke is needed without a long projecting rod

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Rodless cylinders transmit motion through a carriage or magnetic/mechanical arrangement, avoiding the extended external rod length of conventional cylinders.

Q5. A hydraulic motor's case drain is provided mainly to:

A. Remove internal leakage and limit case pressure where required B. Increase cylinder stroke C. Supply electrical power D. Filter the reservoir

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Some motors have a case drain to return leakage oil and protect shaft seals and internal components from excessive case pressure.

Q6. A hydraulic motor is most suitable when the required output is:

A. Long linear stroke only B. Continuous rotary motion C. Static pressure measurement D. Fluid filtration

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Hydraulic motors provide continuous shaft rotation and are widely used for drives, winches, conveyors and mobile machinery.

Q7. The main function of a hydraulic actuator in a fluid-power system is to:

A. Store hydraulic oil permanently B. Filter all contaminants C. Convert hydraulic energy into mechanical output D. Generate electrical power

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: The actuator is the final control element. It receives pressurized flow and converts the fluid's pressure/flow energy into useful force and motion.

Q8. In a meter-out speed-control circuit, flow is controlled at the:

A. Pump suction only B. Reservoir breather C. Pressure gauge D. Actuator outlet

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Meter-out control restricts the fluid leaving the actuator. It is often useful with overrunning loads because it can provide controlled back pressure.

Q9. A gear motor produces rotation using:

A. Meshing gears driven by hydraulic pressure B. A piston rod only C. A spring alone D. A cam follower only

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Pressure forces act on the gear teeth and create torque on the output shaft. Gear motors are simple and robust rotary actuators.

Q10. A cylinder has a 100 mm bore and 60 mm rod. If flow is 18 L/min during retraction, the ideal retraction speed is:

A. 0.0298 m/s B. 0.0597 m/s C. 0.1194 m/s D. 0.239 m/s

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Numerical solution: Annular area = π/4(0.1²−0.06²) = 0.005027 m². Flow = 18 L/min = 0.0003 m³/s. Therefore v = Q/A = 0.0003/0.005027 ≈ 0.0597 m/s.

Q11. The best basic measure to reduce hydraulic actuator shock is to:

A. Increase pressure to maximum B. Remove all cushioning C. Control flow and decelerate the actuator before the end stop D. Use a smaller reservoir only

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Shock is reduced by controlling velocity and decelerating before the mechanical stop. Cylinder cushions, proportional valves and appropriate control profiles are common methods.

Q12. The most common hydraulic rotary actuator that provides continuous rotary motion is:

A. Hydraulic cylinder B. Hydraulic accumulator C. Hydraulic filter D. Hydraulic motor

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Hydraulic motors convert hydraulic energy into continuous shaft rotation. Cylinders generally produce reciprocating linear motion.

Q13. A pressure-compensated flow-control valve is intended to maintain:

A. More nearly constant flow despite load-pressure changes B. Constant reservoir volume only C. Constant cylinder diameter D. Zero pressure drop

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: The compensator adjusts the restriction to maintain a more nearly constant pressure drop across the metering element, stabilizing flow against load changes.

Q14. The main purpose of a hydraulic filter is to:

A. Increase pressure automatically B. Remove contaminants from the fluid C. Create actuator torque D. Replace the reservoir

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Filters capture particles that could damage pumps, valves, seals and actuators, improving reliability and service life.

Q15. Synchronization of two hydraulic cylinders is difficult mainly because:

A. Hydraulic oil is incompressible under every condition B. Both cylinders are always identical C. Loads, leakage and friction can differ between cylinders D. Pressure is always zero

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Even nominally identical cylinders can experience different friction, leakage and loads. Flow-divider, feedback or synchronization control may therefore be required.

Q16. The effective area of a single-rod cylinder during retraction is approximately:

A. Full piston area plus rod area B. Rod area plus bore circumference C. Zero D. Piston area minus rod area

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: On the rod side, the rod occupies part of the piston area. Therefore the pressure-effective annular area is A_p − A_r.

Q17. A hydraulic motor is generally operated with:

A. Pressurized inlet flow and a controlled return path B. No return line C. Only compressed air D. A mechanical spring instead of fluid

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: A continuous hydraulic motor requires fluid circulation: pressurized flow enters and displaced fluid leaves through the return side.

Q18. A cylinder with area 0.005 m² must move at 0.15 m/s. What flow is required?

A. 15 L/min B. 45 L/min C. 30 L/min D. 60 L/min

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Numerical solution: Q = Av = 0.005×0.15 = 0.00075 m³/s = 45 L/min.

Q19. A single-rod cylinder has a 100 mm bore and 50 mm rod. At 8 MPa, the ideal retraction force is:

A. 62.83 kN B. 31.42 kN C. 47.12 kN D. 78.54 kN

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: Piston area = π(0.1)²/4 = 0.007854 m². Rod area = π(0.05)²/4 = 0.001963 m². Annular area = 0.005890 m². Thus F = 8×10⁶×0.005890 ≈ 47.12 kN.

Q20. Air entrainment in hydraulic fluid can cause:

A. Perfectly rigid motion B. Zero compressibility C. Infinite efficiency D. Spongy motion, noise and reduced stiffness

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Entrained air is compressible compared with oil. It can make actuator motion springy, cause noise and reduce control precision.

Q21. Internal leakage in a hydraulic cylinder can cause:

A. Reduced force-holding capability and drift B. Higher theoretical efficiency C. Infinite speed D. Increased piston area

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Leakage across the piston reduces pressure difference and allows unintended movement. This can cause cylinder drift and loss of holding force.

Q22. Hydraulic motor efficiency is important because losses:

A. Increase ideal output without limit B. Reduce useful shaft output and generate heat C. Eliminate pressure requirements D. Make the motor frictionless

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Volumetric, mechanical, and overall losses reduce useful output. The lost energy ultimately appears mainly as heat.

Q23. A rod diameter affects cylinder retraction because it:

A. Increases full-bore area B. Eliminates pressure C. Reduces the effective annular piston area D. Determines oil viscosity

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Retraction force is based on annular area, A_piston − A_rod. A larger rod therefore reduces effective area and force.

Q24. A cylinder with a 100 mm bore has an extension force requirement of 70 kN. Neglecting losses. Required pressure is:

A. 5.00 MPa B. 7.00 MPa C. 12.73 MPa D. 8.91 MPa

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: Area = π(0.1)²/4 = 0.007854 m². Pressure p = F/A = 70,000/0.007854 ≈ 8.91 MPa.

Q25. A hydraulic motor has displacement 250 cm³/rev and runs at 400 rpm. What theoretical flow is required?

A. 100 L/min B. 25 L/min C. 62.5 L/min D. 160 L/min

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: Q = displacement × speed = 250×400 = 100,000 cm³/min = 100 L/min.

Q26. A cylinder is most suitable when the required output is:

A. Continuous rotary motion B. Reciprocating linear motion C. Electrical voltage D. Heat only

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Hydraulic cylinders directly produce linear travel, making them suitable for lifting, clamping, pressing and positioning.

Q27. A cylinder must exert 40 kN at 16 MPa. What minimum piston area is required, neglecting losses?

A. 0.00125 m² B. 0.00400 m² C. 0.00250 m² D. 0.00640 m²

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: A = F/p = 40,000/(16×10⁶) = 0.0025 m².

Q28. A flow-control valve is primarily used to control:

A. Maximum allowable pressure only B. Oil chemical composition C. Cylinder bore diameter D. Actuator speed

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: For a given actuator displacement, speed depends on flow. A flow-control valve meters flow and therefore controls actuator speed.

Q29. A motor has theoretical displacement 120 cm³/rev but requires 132 cm³/rev of actual flow at a given speed. Volumetric efficiency is:

A. 90.9% B. 81.8% C. 91.7% D. 110.0%

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: Volumetric efficiency = theoretical flow/actual flow = 120/132 = 0.9091, or 90.9%.

Q30. A hydraulic accumulator can support an actuator by:

A. Replacing every valve B. Storing hydraulic energy for later release C. Converting oil directly into electricity D. Eliminating pressure fluctuations completely

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: An accumulator stores energy in compressed gas or another mechanism and can release fluid rapidly to supplement pump flow or absorb transients.

Q31. A cushion in a hydraulic cylinder is primarily intended to:

A. Increase oil contamination B. Eliminate the need for a valve C. Reduce impact at the end of stroke D. Convert linear motion to electrical energy

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: End-of-stroke cushioning restricts exhaust flow near the stroke end. The piston decelerates before reaching the mechanical end stop, reducing shock.

Q32. At constant pressure, increasing hydraulic motor displacement generally:

A. Decreases torque and increases speed B. Has no effect C. Eliminates the need for flow D. Increases torque capability and reduces speed for a given flow

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Larger displacement means more fluid volume per revolution. At a given pressure it produces more theoretical torque, while the same flow produces fewer revolutions per minute.

Q33. A trunnion-mounted cylinder is useful when:

A. The cylinder needs to pivot about a mounting axis B. Only electrical output is needed C. No angular movement is permitted D. The cylinder has no rod

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Trunnion mounts provide pivot support, allowing the cylinder body to rotate slightly as the linkage geometry changes.

Q34. A hydraulic cylinder can be used as a hydraulic motor only if:

A. Any standard cylinder can rotate continuously B. Its construction and application are specifically designed for such operation C. No modifications are needed ever D. The reservoir is removed

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Standard cylinders are designed for linear reciprocation. Continuous rotation requires bearings, sealing and structural features suited to rotary service.

Q35. A hydraulic motor with a displacement-control capability is especially useful when:

A. Only fixed speed is acceptable B. No hydraulic pressure is available C. Wide speed range and torque-speed control are required D. Only linear motion is required

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Changing motor displacement changes the fluid volume required per revolution. This permits speed and torque characteristics to be adjusted without changing the mechanical transmission.

Q36. The effective area of a single-rod cylinder during extension is approximately:

A. Piston area minus twice the rod area B. Rod area only C. Zero D. Full piston area

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: During extension, pressure acts on the full piston face on the cap end, so ideal force is pressure times full piston area.

Q37. A 60 mm bore cylinder is supplied with 9 L/min. Its ideal piston speed is:

A. 0.0531 m/s B. 0.0265 m/s C. 0.0796 m/s D. 0.1062 m/s

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: Q = 9 L/min = 0.00015 m³/s. Area = π(0.06)²/4 = 0.002827 m². v = 0.00015/0.002827 ≈ 0.0531 m/s.

Q38. The pressure drop across a valve represents:

A. The cylinder stroke B. Energy loss per unit volume associated with flow through the valve C. The motor displacement D. The reservoir capacity

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: A pressure drop across a flowing restriction represents hydraulic energy converted largely into heat. It is a key factor in system efficiency.

Q39. A cylinder piston moves at 0.2 m/s and has an effective area of 0.003 m². Required flow is:

A. 18 L/min B. 30 L/min C. 36 L/min D. 60 L/min

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: Q = Av = 0.003×0.2 = 0.0006 m³/s. Multiplying by 60,000 gives 36 L/min.

Q40. For a hydraulic motor, displacement is the:

A. Mass of the motor B. Maximum reservoir volume C. Pressure loss in the hose D. Fluid volume theoretically required per shaft revolution

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Motor displacement is commonly expressed in cm³/rev. It indicates the theoretical fluid volume associated with one shaft revolution.

Q41. The main function of a hydraulic reservoir is to:

A. Store and condition hydraulic fluid B. Generate mechanical torque directly C. Control cylinder direction by itself D. Act as the actuator piston

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: The reservoir stores working fluid and provides space for deaeration, heat dissipation, contamination settling and volume changes.

Q42. A rack-and-pinion rotary actuator converts:

A. Rotary motion into electrical energy B. Linear rack motion into rotary pinion motion C. Pressure into stored air D. Spring force into hydraulic pressure

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: A hydraulic piston moves the rack linearly; the rack teeth drive the pinion, producing angular output.

Q43. Hydraulic oil viscosity that is too low can increase:

A. Cylinder bore B. Mechanical advantage without losses C. Internal leakage D. Reservoir capacity

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Lower viscosity generally increases leakage through clearances and can reduce volumetric efficiency, although viscosity selection must match operating conditions.

Q44. A hydraulic motor selected for very high starting torque at low speed is often:

A. A simple pressure gauge B. A reservoir C. A filter D. A radial-piston motor

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Radial-piston motors can develop high torque at low speed because several pistons contribute torque with favorable leverage.

Q45. An axial piston motor has pistons arranged:

A. Parallel or nearly parallel to the drive shaft axis B. Only perpendicular to the shaft in a radial circle C. Inside the reservoir D. Outside the hydraulic circuit

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: In axial piston machines, piston axes are parallel to or nearly parallel with the shaft axis. Swash-plate or bent-axis arrangements are common.

Q46. High motor case pressure can cause:

A. Higher efficiency without limit B. Seal damage or increased leakage in designs sensitive to case pressure C. Zero torque D. Larger displacement automatically

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Excess case pressure can overload shaft seals and alter internal clearances. The allowable case pressure must follow the motor manufacturer's specification.

Q47. A hydraulic cylinder with position feedback can provide:

A. Only open-loop pressure control B. No motion C. Closed-loop position control D. Only manual operation

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: A position sensor measures rod/piston position. The controller can compare actual position with commanded position and correct the valve command.

Q48. A clevis mount allows:

A. Only fixed electrical connection B. Fluid filtration C. Pressure measurement D. Articulated connection and angular movement

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Clevis mounting uses a pin joint so the cylinder can accommodate changing alignment during movement.

Q49. A tandem cylinder is commonly used when the design requires:

A. Higher force from the same pressure with compact diameter B. Only rotary output C. Zero leakage D. No piston rod

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Tandem cylinders place two piston areas in line so their forces add. This increases output force without simply making one piston extremely large.

Q50. A hydraulic intensifier is used to:

A. Increase reservoir size B. Produce higher pressure in a smaller flow circuit from a lower-pressure supply C. Reduce piston area to zero D. Convert continuous rotation into linear motion

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: An intensifier uses unequal piston areas so force balance can generate a higher pressure on the smaller-area side.

Q51. A motor has 125 cm³/rev displacement and runs at 720 rpm. The theoretical flow is:

A. 45 L/min B. 72 L/min C. 90 L/min D. 112.5 L/min

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: Q = VdN = 125×720 = 90,000 cm³/min = 90 L/min.

Q52. In a hydraulic motor circuit, increasing pressure difference at constant displacement generally increases:

A. Reservoir volume B. Motor bore only C. Oil density D. Torque

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Motor torque is proportional to pressure differential and displacement, subject to mechanical losses.

Q53. A single-acting hydraulic cylinder normally develops powered motion in:

A. One direction only B. Both directions equally C. Neither direction D. Only rotational motion

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Pressure is applied to one side of the piston in a single-acting cylinder. Return motion is usually produced by a spring, gravity, or an external load.

Q54. A servo/proportional hydraulic actuator system is characterized by:

A. Operation without sensors in every case B. Precise control of position, velocity or force using controlled flow/pressure C. Only on/off motion D. No need for a valve

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Servo and proportional systems use controlled valves and feedback or command signals to regulate actuator behavior more precisely than simple on/off circuits.

Q55. A vane motor develops torque primarily because pressure acts on:

A. A piston rod B. A rack only C. Differential areas of vanes D. A reservoir wall

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Pressure acts on vane surfaces. The resulting force difference across the vanes creates a torque that rotates the rotor.

Q56. Cavitation in a hydraulic motor or pump is associated with:

A. Excessive fluid viscosity only B. A completely blocked exhaust with no pressure effects C. Electrical insulation failure D. Local vapor formation due to inadequate inlet pressure

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: When local pressure falls below the fluid's vapor pressure, vapor bubbles form and can collapse violently, causing noise, damage and performance loss.

Q57. A cylinder buckling risk is especially important for:

A. Long slender rods under compressive loading B. Very short rods in tension only C. Reservoir walls D. Flexible hoses under no load

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: A long slender cylinder rod under compression can buckle. Rod diameter, unsupported length, mounting and load direction must be considered.

Q58. A hydraulic motor with high volumetric efficiency has:

A. Large external leakage B. Low internal leakage relative to ideal displacement flow C. No pressure requirement D. Zero mechanical friction

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Volumetric efficiency compares useful theoretical displacement flow with actual flow requirements. Lower leakage generally improves it.

Q59. A hydraulic rotary actuator that gives limited angular motion rather than continuous rotation is:

A. Gear pump B. Linear cylinder C. Vane-type rotary actuator D. Reservoir

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Rotary actuators can use vanes or racks and pinions to produce limited angular displacement, unlike continuous hydraulic motors.

Q60. The main difference between a hydraulic motor and a hydraulic pump is the intended energy conversion:

A. Both always convert hydraulic to electrical B. Pump: hydraulic to mechanical only C. There is no functional difference D. Motor: hydraulic to mechanical; pump: mechanical to hydraulic

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: A pump is driven mechanically to create hydraulic flow/pressure capability, while a motor consumes hydraulic energy to produce shaft power.

Q61. The direction of a hydraulic cylinder is commonly controlled by:

A. Directional control valve B. Reservoir breather only C. Pressure gauge only D. Filter element only

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: A directional control valve routes pressurized fluid to the desired cylinder port and provides a return path from the opposite chamber.

Q62. In a standard double-acting cylinder, the retraction force is lower than extension force mainly because:

A. Pressure disappears during retraction B. Rod area reduces the effective annular area C. The cylinder becomes single acting D. The oil density becomes zero

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: During retraction, pressure acts over piston area minus rod area. The annular area is therefore smaller than the full piston area.

Q63. A telescopic hydraulic cylinder is especially useful when:

A. Only very small forces are required B. Only rotary motion is required C. A long stroke is needed with a short retracted length D. No extension is required

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Telescopic cylinders use nested stages. They can produce a long overall stroke while occupying a relatively short length when retracted.

Q64. The term 'hydraulic horsepower' relates to:

A. Cylinder rod diameter only B. Oil viscosity only C. Reservoir height only D. Pressure and flow power available in the fluid

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Fluid power is the product of pressure and flow with appropriate units. It represents the hydraulic power available to the actuator.

Q65. A hydraulic motor develops 200 N·m ideal torque with a displacement of 100 cm³/rev. What pressure difference is required?

A. 12.57 MPa B. 6.28 MPa C. 8.00 MPa D. 25.13 MPa

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: From T = ΔpVd/(2π), Δp = 2πT/Vd = 2π(200)/(100×10⁻⁶) ≈ 12.57 MPa.

Q66. The torque of an ideal hydraulic motor is primarily related to:

A. Oil color and tank size B. Pressure difference and motor displacement C. Hose diameter alone D. Reservoir temperature alone

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Motor torque increases with pressure differential and displacement. In simplified form, T is proportional to Δp times displacement.

Q67. A hydraulic motor has displacement 100 cm³/rev and receives 30 L/min. Neglecting leakage, its speed is:

A. 100 rpm B. 200 rpm C. 300 rpm D. 600 rpm

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: Flow per minute is 30,000 cm³/min. Speed N = Q/Vd = 30,000/100 = 300 rev/min.

Q68. A through-rod cylinder has:

A. No piston B. Only one fluid port C. Only rotary output D. A rod extending from both ends of the piston

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: A through-rod or double-rod cylinder has rod extensions on both sides. The equal rod areas can provide similar effective areas in both directions.

Q69. A cylinder has a bore of 70 mm. At 7 MPa, what ideal extension force is produced?

A. 26.95 kN B. 13.48 kN C. 19.25 kN D. 38.48 kN

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: Area = π(0.07)²/4 = 0.003848 m². F = 7×10⁶×0.003848 ≈ 26.94 kN.

Q70. The speed of an ideal hydraulic motor is primarily related to:

A. Pressure alone B. Flow rate and motor displacement C. Reservoir volume alone D. Oil color

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Motor speed is approximately proportional to supplied flow divided by displacement. Increasing flow increases speed, while increasing displacement reduces speed for the same flow.

Q71. A hydraulic cylinder converts hydraulic energy primarily into:

A. Rotary mechanical motion B. Electrical energy C. Linear mechanical motion D. Thermal energy

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: A cylinder uses pressurized fluid acting on a piston area to produce force and piston displacement. The piston rod therefore provides linear mechanical output.

Q72. A hydraulic motor delivers 20 kW shaft power at 1000 rpm. Its output torque is approximately:

A. 95.5 N·m B. 200 N·m C. 318 N·m D. 191 N·m

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: T = P/ω. Angular speed ω = 2πN/60 = 104.72 rad/s. T = 20,000/104.72 ≈ 191 N·m.

Q73. A hydraulic actuator should be sized considering:

A. Force/torque, speed, pressure, stroke/rotation and duty cycle B. Only its color C. Only reservoir size D. Only hose length

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Proper sizing must satisfy the required mechanical output and motion while remaining within pressure, speed, temperature and duty-cycle limits.

Q74. A hydraulic motor of 160 cm³/rev receives 48 L/min. Its theoretical speed is:

A. 150 rpm B. 300 rpm C. 240 rpm D. 480 rpm

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Numerical solution: Q = 48,000 cm³/min. N = Q/Vd = 48,000/160 = 300 rpm.

Q75. A larger hydraulic hose, for the same flow and fluid, generally tends to:

A. Increase flow velocity greatly B. Eliminate all leakage C. Reduce flow velocity and pressure loss D. Increase oil density

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: For a fixed flow rate, velocity is lower in a larger cross-sectional area. Lower velocity generally reduces frictional pressure loss.

Q76. A hydraulic system operates at 14 MPa and 25 L/min. The ideal hydraulic power is approximately:

A. 3.50 kW B. 8.75 kW C. 14.58 kW D. 5.83 kW

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: Power P = pQ. Q = 25 L/min = 25×10⁻³/60 = 0.0004167 m³/s. P = 14×10⁶×0.0004167 ≈ 5833 W = 5.83 kW.

Q77. A pressure relief valve primarily protects a hydraulic system from:

A. Excessive pressure B. Low oil level only C. Incorrect motor direction D. Excessive reservoir volume

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: The relief valve opens when system pressure reaches its setting, diverting flow and limiting pressure to protect components.

Q78. A flow divider can be used to:

A. Increase oil temperature intentionally B. Split flow between branches in a controlled ratio C. Replace all actuators D. Measure cylinder stroke directly

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Flow dividers distribute a pump flow between branches. They are useful when two actuators must move in a coordinated manner, within the device's accuracy limits.

Q79. For a cylinder with piston area 0.004 m² and pressure 10 MPa, the ideal force is:

A. 20 kN B. 25 kN C. 40 kN D. 100 kN

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: F = pA = 10×10⁶×0.004 = 40,000 N = 40 kN.

Q80. A cylinder has a 50 mm bore and is supplied with 12 L/min. What is the ideal extension speed?

A. 0.051 m/s B. 0.204 m/s C. 0.408 m/s D. 0.102 m/s

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: Q = 12 L/min = 0.0002 m³/s. Area = π(0.05)²/4 = 0.001963 m². Speed v = Q/A = 0.0002/0.001963 ≈ 0.102 m/s.

Q81. A rotary vane actuator's angular travel is limited mainly by:

A. Internal vane stops and chamber geometry B. Reservoir color C. Hose length only D. Oil density

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: The vane sweeps through a bounded chamber. Mechanical stops and the housing geometry define its angular range.

Q82. Hydraulic actuator seals are primarily intended to:

A. Increase oil density B. Prevent internal and external fluid leakage C. Generate pressure without a pump D. Measure displacement

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Seals separate pressure zones and prevent fluid escaping from the actuator or bypassing the piston, thereby maintaining performance.

Q83. A counterbalance valve is particularly useful with a vertical cylinder because it:

A. Increases oil contamination B. Eliminates the pump C. Helps prevent uncontrolled downward movement D. Makes the cylinder single acting

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: A counterbalance valve creates controlled back pressure and prevents a suspended load from running away due to gravity.

Q84. A cylinder produces 60 kN ideal force but friction and other mechanical losses reduce useful force to 54 kN. Mechanical efficiency is:

A. 80% B. 85% C. 95% D. 90%

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: Mechanical efficiency = useful output/ideal output = 54/60 = 0.90 = 90%.

Q85. A cylinder has a 80 mm bore and 40 mm rod. At 6 MPa, the ideal retraction force is:

A. 22.62 kN B. 18.85 kN C. 28.27 kN D. 37.70 kN

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: Annular area = π/4(0.08²−0.04²) = 0.003770 m². Therefore F = 6×10⁶×0.003770 ≈ 22.62 kN.

Q86. The force developed by a hydraulic cylinder is fundamentally determined by pressure and:

A. Oil color B. Effective piston area C. Reservoir volume alone D. Hose length alone

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: For a cylinder, ideal force is F = pA. Thus, for a given pressure, a larger effective piston area produces greater force.

Q87. A hydraulic actuator's speed is most directly controlled by changing:

A. Fluid color B. Cylinder material only C. Flow rate D. Seal hardness only

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: For a cylinder, speed is approximately Q/A. For a motor, speed is approximately Q/displacement. Thus flow control directly affects speed.

Q88. A hydraulic cylinder has a bore diameter of 80 mm and operates at 10 MPa. Neglecting losses, what extension force is produced?

A. 25.13 kN B. 40.00 kN C. 64.00 kN D. 50.27 kN

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: Piston area A = πD²/4 = π(0.08)²/4 = 0.005027 m². Force F = pA = 10×10⁶×0.005027 = 50,270 N ≈ 50.27 kN.

Q89. A hydraulic motor is best described as a device that converts:

A. Fluid power into rotary mechanical power B. Rotary power into fluid pressure only C. Electrical power into heat D. Mechanical energy into stored oil

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Pressure and flow supplied to a hydraulic motor produce torque and rotational speed at its shaft.

Q90. A hydraulic cylinder with high mechanical efficiency has:

A. Large seal friction only B. Small mechanical/friction losses relative to ideal force C. No need for lubrication D. Zero pressure

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: Mechanical efficiency reflects losses from friction and mechanical effects. Lower friction gives output force closer to the ideal pressure-area force.

Q91. A hydraulic motor consumes 45 L/min at 600 rpm. Its actual displacement based on supplied flow is:

A. 50 cm³/rev B. 60 cm³/rev C. 75 cm³/rev D. 90 cm³/rev

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Numerical solution: Displacement = Q/N = 45,000 cm³/min / 600 rev/min = 75 cm³/rev.

Q92. A fixed-displacement hydraulic motor has:

A. Continuously adjustable displacement by definition B. No shaft C. No need for a pump D. Approximately constant displacement per revolution

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: In a fixed-displacement motor, the geometric displacement per revolution is fixed. Speed can still vary with supplied flow.

Q93. A radial piston motor is generally characterized by:

A. Pistons arranged radially around a shaft or eccentric element B. Only axial gears C. A single flexible hose D. A spring-loaded reservoir

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Explanation: Radial piston motors place multiple pistons around the rotor. They can provide high torque, especially at low speed.

Q94. A pilot-operated check valve is commonly used to:

A. Increase reservoir capacity B. Lock an actuator while permitting release by pilot pressure C. Measure temperature D. Generate continuous rotary motion

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: A check valve blocks flow in one direction. Pilot pressure can open it intentionally, allowing controlled release of a locked actuator.

Q95. A cylinder with a larger bore at the same pressure generally produces:

A. Lower extension force B. Only higher speed regardless of flow C. Greater extension force D. No force

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Because F = pA and piston area increases with the square of diameter, a larger bore produces greater force at the same pressure.

Q96. Hydraulic actuators are often preferred for heavy-duty motion because they provide:

A. No need for seals B. Zero energy losses C. No maintenance requirements D. High force/torque density and controllable motion

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Explanation: Hydraulic systems can transmit high power through compact actuators. They also provide controllable force and speed, although losses and maintenance remain important.

Q97. A motor has displacement 200 cm³/rev and operates at 100 bar pressure difference. Ideal torque is:

A. 318.3 N·m B. 159.2 N·m C. 200 N·m D. 400 N·m

Check Answer

Correct Answer: A   |   Marks: 1

Explanation: Numerical solution: 100 bar = 10 MPa. T = ΔpVd/(2π) = 10×10⁶×200×10⁻⁶/(2π) ≈ 318.3 N·m.

Q98. A double-acting cylinder differs from a single-acting cylinder because it:

A. Requires no hydraulic fluid B. Can be powered in both extension and retraction C. Produces only rotary motion D. Always contains a return spring

Check Answer

Correct Answer: B   |   Marks: 1

Explanation: Explanation: A double-acting cylinder has two fluid ports. Pressure can be directed alternately to opposite sides of the piston, allowing controlled powered motion in both directions.

Q99. A variable-displacement hydraulic motor allows:

A. Only electrical speed control B. Removal of all pressure losses C. Adjustment of displacement and hence speed/torque characteristics D. Operation without hydraulic fluid

Check Answer

Correct Answer: C   |   Marks: 1

Explanation: Explanation: Changing motor displacement changes the relationship among flow, speed, torque and pressure, allowing wider operating control.

Q100. A motor has displacement 80 cm³/rev and operates at a pressure difference of 12 MPa. Its ideal torque is approximately:

A. 76.4 N·m B. 96.0 N·m C. 240.0 N·m D. 152.8 N·m

Check Answer

Correct Answer: D   |   Marks: 1

Explanation: Numerical solution: Ideal torque T = Δp Vd/(2π). With Vd = 80 cm³/rev = 80×10⁻⁶ m³/rev, T = 12×10⁶×80×10⁻⁶/(2π) ≈ 152.8 N·m.