# Hydraulic System and Components - 2 - MCQs and Answers

## Hydraulic System and Components – 2 – MCQs and Answers

1. Positive displacement pump used in hydraulic systems have

a. high viscosity of fluids
b. low efficiency
c. required volume of fluid cannot be discharged
d. all the above

ANSWER: a. high viscosity of fluids

2. Electric motor has a speed of 1200 rpm and output rate of pump is 6 cc/rev. Calculate flow rate of pump in l/min

a. 6 l/min
b. 7.2 l/min
c. 5 l/min
d. none of the above

3. Calculate the power absorbed by the pump if, it has a flow rate of 20 cc/rev and develops a maximum pressure of 70 bar, when electric motor runs at a speed of 1200 rpm.

a. 1.9 kW
b. 2.8 kW
c. 2.3 kW
d. none of the above

4. Volumetric efficiency is the ratio of

a. theoretical flow rate to actual flow rate
b. actual flow rate to theoretical flow rate
c. actual fluid power to pump input power
d. none of the above

ANSWER: b. actual flow rate to theoretical flow rate

5. Which of the following is a hydrodynamic pump?

a. vane pump
b. centrifugal pump
c. gear pump
d. piston pump

6. 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 the above

ANSWER: c. 1, 2 and 3

7. 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

8. 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

ANSWER: b. two gears rotate in opposite direction

9. 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