1) At which pressure, petroleum oil used in hydraulic systems gets compressed by 1/2%?
a. 70 bar
b. 40 bar
c. 30 bar
d. 95 bar
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2) What is the relation between temperature and specific weight for water glycol?
a. as temperature increases specific weight decreases
b. as temperature increases specific weight increases
c. temperature and specific weight vary linearly
d. none of the above
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Answer
Explanation
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ANSWER: as temperature increases specific weight decreases
Explanation:
No explanation is available for this question!
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3) What is the relation between temperature and viscosity for hydraulic oil?
a. temperature and viscosity vary linearly
b. as temperature decreases viscosity decreases at atmospheric pressure
c. as temperature increases viscosity decreases at atmospheric pressure
d. none of the above
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Answer
Explanation
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ANSWER: as temperature increases viscosity decreases at atmospheric pressure
Explanation:
No explanation is available for this question!
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4) Match the following group 1 with group 2 and select the correct option:
Group 1 ---------------------------------------- Group 2
1. High water fluids ---------------------------- A. Water and synthetic chemical
2. Water in oil ------------------------------------ B. Fire-resistant fluid
3. Water glycol ----------------------------------- C. Oil in water
4. Synthetics -------------------------------------- D. Tiny droplets of water in oil
a. C – D – A – B
b. D – C – B – A
c. C – B – D – A
d. D – C – A – B
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5) High Water Fluids contain
a. oil in water
b. water in oil
c. only water
d. none of the above
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6) Viscosity of High Water Fluid is
a. greater than water
b. less than water
c. nearby water
d. none of the above
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7) Adding an additive to water glycol fluids improves
a. flammability
b. viscosity
c. oxidation
d. all of the above
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8) What is the characteristic of turbulent flow?
a. high velocity
b. the direction of flow and movement of particles is same
c. change in cross section does not affect the flow
d. all of the above
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9) Which flow pattern gets affected when cross section of the pipe is changed?
a. laminar flow
b. turbulent flow
c. laminar and turbulent
d. none of the above
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10) Which of the following statements is/are true according to Bernoulli's principle?
1. If a system has constant flow rate, change in cross-section area of the pipe affects the total energy of system
2. The change in cross-section has no effect on the total energy of the system and is constant if it has varying flow rate
3. A system has constant total energy, if flow rate is constant and change in cross-section has no effect on total energy
a. Statement 1
b. Statement 2
c. Statement 3
d. all of the above
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11) Speed of the actuator is affected by
a. cross-section area of the orifice
b. velocity of flow
c. pipe diameter
d. all of the above
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12) Why according to Bernoulli's principle, change in cross-section area of the pipe has no effect on total energy of the system?
a. when area of pipe increases upstream, kinetic energy of fluid decreases as velocity of fluid increases and potential energy increases
b. when area of pipe increases upstream, kinetic energy of fluid decreases as velocity of fluid decreases and potential energy increases
c. when area of pipe increases upstream, kinetic energy of the fluid increases as velocity of fluid decreases and potential energy decreases
d. when area of pipe increases upstream, kinetic energy of fluid increases as velocity of fluid increases and potential energy decreases
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Answer
Explanation
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ANSWER: when area of pipe increases upstream, kinetic energy of fluid decreases as velocity of fluid decreases and potential energy increases
Explanation:
No explanation is available for this question!
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13) In which of these applications Bernoulli's principle is widely used?
a. design of blowers
b. design of aircraft wings
c. design of propellers
d. all of the above
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14) The total energy developed by the hydraulic oil in a system is given as
a. Total energy = (Potential energy + Pressure energy)
b. Total energy = (Potential energy + Kinetic energy)
c. Total energy = (Potential energy – Kinetic energy)
d. none of the above
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Answer
Explanation
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ANSWER: Total energy = (Potential energy + Kinetic energy)
Explanation:
No explanation is available for this question!
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15) If a pump gives higher flow rate to the valve then, pressure drop in the valve
a. increases
b. decreases
c. remains the same
d. none of the above
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16) Match the following Group-1 with Group-2 and select the correct answer from the options below
(A) pressure head -------------------------- (1) μ / ρ
(B) velocity head ---------------------------- (2) vd / ν
(C) kinematic viscosity --------------------- (3) v2 /ρg
(D) Reynolds number ----------------------- (4) p / ρg
-----------------------------------------------------(5) v2 / 2 g
a. A-(5), B-(3), C-(2), D-(1)
b. A-(4), B-(1), C-(3), D-(2)
c. A-(4), B-(5), C-(1), D-(2)
d. A-(3), B-(5), C-(2), D-(1)
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17) In Reynolds number (ρvd) / μ, the letter μ denotes
a. kinematic viscosity
b. absolute viscosity
c. coefficient of friction
d. none of the above
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18) The ratio of inertia force to viscosity is known as
a. Biot number
b. Reynold number
c. Cauchy number
d. Euler number
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19) The Reynolds number for laminar flow is
a. more than 2800
b. more than 2000
c. less than 2000
d. between 2000 and 2800.
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20) A pipe has a diameter of 0.2 m in which a fluid flows with a velocity of 0.3 m3/s. Determine whether the flow is laminar or turbulent calculating the Reynolds number. Assume kinematic viscosity = 0.5 × 10-4 m2 /s.
a. the flow is laminar having Reynolds number 1200
b. the flow is turbulent having Reynolds number 2100
c. the flow is laminar having Reynolds number 2200
d. the flow is neither laminar nor turbulent
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Answer
Explanation
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ANSWER: the flow is laminar having Reynolds number 1200
Explanation:
No explanation is available for this question!
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21) What is the advantage of internal gear pump?
a. moderate speed
b. medium pressure
c. high viscosity fluids can be used
d. all of the above
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22) The rotation of which inner element causes the liquid to pump out in centrifugal pumps?
a. internal gear
b. rotation of the impeller
c. cylinder rotor
d. none of the above
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23) Which force causes vanes to come out of the rotor slots?
a. centripetal force
b. centrifugal force
c. friction force
d. none of the above
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24) Which of the following statements is true?
a. combination of stator with rotor is known as cartridge unit
b. combination of stator with vanes is known as cartridge unit
c. combination of rotor with vanes is known as cartridge unit
d. none of the above
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Answer
Explanation
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ANSWER: combination of rotor with vanes is known as cartridge unit
Explanation:
No explanation is available for this question!
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25) What is the advantage of flexible vane pump?
a. they can handle solids which are of large size
b. they can create good vacuum
c. both a. and b.
d. none of the above
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26) Cartridge kits generate pumping chambers of various sizes, which
a. increase the flow rate
b. decrease the flow rate
c. increase and decrease the flow rate
d. none of the above
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27) Which of the following statements is false for vane pumps?
a. wear in contact surfaces occurs due to continuous contact between vane tips and the cam ring
b. different sizes of cartridge kits can be replaced in same vane pump
c. elliptical cam ring is replaced by round cam ring to reduce unbalanced forces
d. none of the above
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Answer
Explanation
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ANSWER: elliptical cam ring is replaced by round cam ring to reduce unbalanced forces
Explanation:
No explanation is available for this question!
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28) Balanced vane pumps are designed to have
a. fixed displacement
b. variable displacement
c. both fixed and variable displacement
d. none of the above
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29) Cam ring of unbalanced vane pump is
a. round
b. elliptical
c. both a. and b.
d. none of the above
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30) In pressure compensated vane pump,
1. having variations in eccentricity between rotor and cam ring gives variable displacement
2. as eccentricity between rotor and cam decreases, flow of fluid decreases
3. as eccentricity between rotor and cam decreases, flow of fluid increases
4. having variations in eccentricity between rotor and cam ring gives fixed displacement
a. 1 and 3
b. 3 and 4
c. 2 and 4
d. 1 and 2
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31) Variable displacement pumps used in hydraulic applications can
1. have variable flow rate
2. consume less energy
3. be operated with high accuracy for slow and rapid motion
4. generate more heat
a. 1 and 2
b. 3 and 4
c. 1, 2 and 3
d. all of the above
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32) Which type of displacement is observed in gear pumps?
a. only variable displacement
b. only fixed displacement
c. both fixed and variable displacement
d. none of the above
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33) What is the principle of operation used in gear pumps?
a. two gears rotate in same direction
b. two gears rotate in opposite direction
c. both a. and b.
d. none of the above
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34) What causes suction of fluid into the gear pump?
a. when pressure drops during disengagement of teeth at the suction side
b. when pressure increases during disengagement of teeth at the suction side
c. when pressure drops during engagement of teeth at the suction side
d. when pressure increases during engagement of teeth at the suction side
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Answer
Explanation
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ANSWER: when pressure drops during disengagement of teeth at the suction side
Explanation:
No explanation is available for this question!
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35) How is the smooth and continuous discharge of fluid achieved in a gear pump?
a. increasing number of teeth
b. decreasing number of teeth
c. none of the above
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36) What cause discharge of fluid in an external gear pump?
1. the electric motor drives one gear which turns the other gear
2. the electric motor drives both the gears simultaneously
3. fluid passes between the gears to discharge side
4. fluid passes through interior of the casing between teeth and casing and not between the gears
a. 1 and 3
b. 2 and 3
c. 1 and 4
d. 2 and 4
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37) The rotation of gears in internal gear pump takes place in
a. same direction
b. different direction
c. none of the above
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38) How does the fluid flow in internal gear pump?
a. fluid enters the suction side between rotor, which is a large exterior gear and idler which is a small interior gear
b. fluid enters the suction side between rotor, which is a small exterior gear and idler which is a large interior gear
c. fluid enters the suction side between rotor and idler which rotate in different directions
d. none of the above
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Answer
Explanation
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ANSWER: fluid enters the suction side between rotor, which is a large exterior gear and idler which is a small interior gear
Explanation:
No explanation is available for this question!
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39) What causes internal leakage in internal gear pump?
a. less tolerance level between the meshing surfaces
b. more tolerance level between the meshing surfaces
c. no tolerance between the meshing surfaces
d. none of the above
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Answer
Explanation
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ANSWER: more tolerance level between the meshing surfaces
Explanation:
No explanation is available for this question!
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40) What is the relation between pressure and overall efficiency for a gear pump?
a. as pressure increases, overall efficiency decreases
b. as pressure increases, overall efficiency increases
c. overall efficiency is not affected by change in pressure
d. cannot say
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Answer
Explanation
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ANSWER: as pressure increases, overall efficiency decreases
Explanation:
No explanation is available for this question!
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41) 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
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Answer
Explanation
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ANSWER: telescopic cylinders give greater stroke length than standard cylinder
Explanation:
No explanation is available for this question!
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42) 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
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43) Telescopic cylinders have
a. only two stage units
b. only three stage units
c. two or three stage units
d. multistage units
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44) 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
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45) 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 of the above
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46) 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 of the above
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47) 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
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48) Which of the following is used for mounting purpose in hydraulic cylinders?
a. Female clevis
b. Circular flange
c. Trunnion
d. all of the above
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49) 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
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Answer
Explanation
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ANSWER: cushioning decreases the speed of piston near the extreme ends of the cylinder
Explanation:
No explanation is available for this question!
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50) 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
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