##### Q51. The boundary layer takes place

(a) for ideal fluids
(b) for pipe flow only
(c) for real fluids
(d) for flow over flat plate only.

Ans:  (c) for real fluids

##### Q52. The boundary layer is called turbulent boundary layer if

(a) Reynold number is more than 2000
(b) Reynold number is more than 4000
(c) Reynold number is more than 5 × 10
(d) None of the above.

Ans:  (c) Reynold number is more than 5 × 105

##### Q53. Laminar sub-layer exists in

(a) laminar boundary layer region
(b) turbulent boundary layer region
(c) transition zone
(d) none of the above.

Ans:  (b) turbulent boundary layer region

##### Q54. Drag is defined as the force exerted by a flowing fluid on a solid body

(a) in the direction of flow
(b) perpendicular to the direction of flow
(c) in the direction which is at an angle of 45° to the direction of flow
(d) none of the above.

Ans:  (a) in the direction of flow

##### Q55. Lift force is defined as the force exerted by a flowing fluid on a solid body

(a) in the direction of flow
(b) perpendicular to the direction of flow
(c) at an angle of 45° to the direction of flow
(d) none of the above.

Ans:  (b) perpendicular to the direction of flow

##### Q56. The boundary layer separation takes place if

(a) pressure gradient is zero
(b) pressure gradient is +ve
(c) pressure gradient is negative
(d) none of the above.

Ans:  (b) pressure gradient is +ve

##### Q57. Boundary layer on a flat plate is called laminar boundary layer if

(a) Reynold number is less than 2000
(b) Reynold number is less than 4000
(c) Reynold number is less than 5 × 10
(d) None of the above.

Ans:  (c) Reynold number is less than 5 × 10

##### Q58. Boundary layer thickness (δ) is the distance from the surface of the solid body in the direction perpendicular to flow, where the velocity of fluid is equal to

(a) Free stream velocity
(b) 0.9 times the free stream velocity
(c) 0.99 times the free stream velocity
(d) None of the above.

Ans:  (c) 0.99 times the free stream velocity

##### Q59. Kinematic similarity between model and prototype means

(a) the similarity of forces
(b) the similarity of shape
(c) the similarity of motion
(d) the similarity of discharge.

Ans:  (c) the similarity of motion

##### Q60. Dynamic similarity between model and prototype means

(a) the similarity of forces
(b) the similarity of motion
(c) the similarity of shape
(d) none of the above.

Ans:  (c) the similarity of shape

DEAR READERS IF YOU FIND ANY ERROR/TYPING MISTAKE PLEASE LET ME KNOW IN THE COMMENT SECTIONS OR E-MAIL: [email protected]

##### Read More Sections of Automobile Engineering

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Hydraulics and Fluid mechanics MCQ-Section-1

Hydraulics and Fluid mechanics MCQ-Section-2

Hydraulics and Fluid mechanics MCQ-Section-3

Hydraulics and Fluid mechanics MCQ-Section-4

Hydraulics and Fluid mechanics MCQ-Section-5