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1) For any operation in a hydraulic system the fluid should have pour point a. 20 °F below the lowest temperature b. 20 °F above the lowest temperature c. 20 °C below the lowest temperature d. 20 °C above the lowest temperature
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2) What is the disadvantage of petroleum based fluids? a. low flash point b. low density c. light weight d. all of the above
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3) How is the water content in High Water Fluids (HFA) compared to oil content? a. more oil than water b. oil and water are in same proportion c. more water than oil d. contains only water
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4) A fluid used in hydraulic systems should have a. low oxidation resistance b. high oxidation resistance c. high oxidation enhancing ability d. none of the above
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5) 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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6) 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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7) 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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8) High Water Fluids contain a. oil in water b. water in oil c. only water d. none of the above
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9) 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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10) Adding an additive to water glycol fluids improves a. flammability b. viscosity c. oxidation d. all of the above
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11) 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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12) 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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13) 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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14) 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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15) 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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16) 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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17) 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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18) 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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19) 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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20) 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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