Fluid Mechanics (General Engineering) (SSC JE)

Total Questions: 50

11. To avoid cavitation in centrifugal pumps [JPSC AE (GEN. ENGG)-2013 ]

Correct Answer: (c) suction pressure should be high
Solution:

To avoid cavitation in centrifugal pumps suction pressure should be high because cavitation occurs the liquid in a pump turn to a vapour at low pressure.
It occurs because there is not enough pressure at the suction end of the pump. As the liquid passes from region of low pressure to higher pressure the air bubble explode.

12. Match list-I with List-II and select the correct answer using the code given below the Lists : [JPSC AE (GEN. ENGG)-2013 ]

Correct Answer: (b) a-4, b-3, c-1, d-2
Solution:

13. The equation of a velocity distribution over a plate is given by u = 2y – y², where u is the velocity in m/s at a point y meter from the plate measured perpendicularly. Assuming, µ = 8.60 poise, the shear stress at a point 15 cm from the boundary is [JPSC AE (GEN. ENGG)-2013 ]

Correct Answer: (b) 1.46 N/m²
Solution:

14. For turbulent boundary layer flow, the thickness of laminar sublayer δ is given by [JPSC AE (GEN. ENGG)-2013 ]

Correct Answer: (b)
Solution:

15. In a fully turbulent flow through a rough pipe, the friction factor f is (Rₑ is the Reynolds number and k/D is relative roughness) [JPSC AE (GEN. ENGG)-2013 ]

Correct Answer: (b) a function of Re and k/D
Solution:

In a fully turbulent flow through a rough pipe, the friction factor f is a function of Re and k/D.
Turbulent flow–

16. A cylinder of height 20.05 m is completely filled with water. The velocity of efflux of water through a small hole on the side wall of the cylinder 5cm above its bottom, is : [JSSC JE (GEN. ENGG.)- 03.07.2022 ]

Correct Answer: (b) 20 m/s
Solution:

17. Find the mismatch [JSSC JE (GEN. ENGG.)- 03.07.2022 ]

Correct Answer: (b)
Solution:

18. Find the mismatch [JSSC JE (GEN. ENGG.)- 03.07.2022 ]

Correct Answer: (b)
Solution:

19. Water hammer occurs in [JSSC JE (GEN. ENGG.)- 03.07.2022 ]

Correct Answer: (b) Penstock
Solution:

Water hammer is developed in a penstock. It is developed due to the reduction in lead on the generator. This reduction causes the governor to close the turbine gates and thus creating an increased pressure in the penstock.

20. Which of the following laws states that the pressure at any point in a fluid at rest has the same magnitude in all directions? [RRB JE (Ranchi) 04.01.2015 / JSSC JE (GEN. ENGG.)- 03.11.2022 ]

or
'In a static fluid, the intensity of pressure will be equal in all directions.' This was stated by:

Correct Answer: (b) Pascal
Solution:

Pascal's law is a principle in fluid mechanics given by Blaise Pascal "that states that intensity of pressure or pressure at a point in a static fluid is equal in all direction i.e. at a point A".