# Basics of Hydraulics - Mechanical Engineering (MCQ) questions and answers

1)   How is laminar flow characterized in a straight pipe?

a. flow of high shear stress
b. flow of high velocity
c. flow of low-velocity
d. none of the above
 Answer  Explanation ANSWER: flow of low-velocity Explanation: No explanation is available for this question!

2)   The resistance offered to the flow of fluid inside a piston develops into

a. pressure
b. force
c. stress
d. all of the above
 Answer  Explanation ANSWER: pressure Explanation: No explanation is available for this question!

3)   Generally liquids are non-compressible but when a large pressure of 70 bar is applied, petroleum oil can be compressed up to

a. 0.5% of its original volume
b. 1% of its original volume
c. 5% of its original volume
d. none of the above
 Answer  Explanation ANSWER: 0.5% of its original volume Explanation: No explanation is available for this question!

4)   Which formula is used to calculate head loss in valves?

a. K2 ( v / 2 g )
b. K ( v / 2 g )
c. K ( v2 / 2 g )
d. none of the above
 Answer  Explanation ANSWER: K ( v2 / 2 g ) Explanation: No explanation is available for this question!

5)   Calculate area of a pipe if, flow rate is 20 l/min and flow velocity is 5 cm/s.

a. 66.66 cm2
b. 60 cm2
c. 62 cm2
d. none of the above
 Answer  Explanation ANSWER: 66.66 cm2 Explanation: No explanation is available for this question!

6)   What are the reasons causing pressure drop in hydraulic systems?

1. long length of pipe
2. friction
3. type of fluid
4. losses in valves and bends

a. 1 and 4
b. only 1
c. 2 and 3
d. all of the above
 Answer  Explanation ANSWER: all of the above Explanation: No explanation is available for this question!

7)   Head loss due to friction (hf) is a function of

3. length to diameter ratio
4. diameter to length ratio
5. friction factor

a. 1, 2 and 3
b. 1, 4 and 5
c. 1, 3 and 5
d. all of the above
 Answer  Explanation ANSWER: 1, 3 and 5 Explanation: No explanation is available for this question!

8)   Head loss hf due to friction is given by

a. 4 ƒ l v2 / g d
b. 4 f2 l ν / 2 g d
c. 2 ƒ l v 2 / 2 g d
d. 4 ƒ l v2 / 2 g d
 Answer  Explanation ANSWER: 4 ƒ l v2 / 2 g d Explanation: No explanation is available for this question!

9)   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
 Answer  Explanation ANSWER: 1 and 2 Explanation: No explanation is available for this question!

10)   Cam ring of unbalanced vane pump is

a. round
b. elliptical
c. both a. and b.
d. none of the above
 Answer  Explanation ANSWER: round Explanation: No explanation is available for this question!

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