Fluid Mechanics Multiple Choice Questions
1- An ideal fluid is a fluid
(A) which obeys Newton’s law of viscosity
(B) which is incompressible and is having no viscosity
(C) in which shear stress is directly proportional to the rate of shear strain
(D) in which the boundary layer is zero.
2- In a Bernoulli’s theorem, which states that in a steady, ideal flow of an incompressible fluid, the total energy at point of the fluid is constant, the units of the various energies are in
(A) Joules
(B) Kilo-watt hour
(C) Meters
(D) Meter / Second2
3- A path line is a concept given by
(A) Lagrangian
(B) Euler
(C) Colebrook
(D) Bernoulli
4- A pressure relief valve is provided to prevent
(A) The water flowing out of the suction pipe
(B) The backflow when the pump is stopped
(C) The increase of pressure after safe limit
(D) All of the above
5- In laminar flow through a round tube, the discharge varies
(A) linearly as viscosity
(B) inversely as viscosity
(C) linearly as the radius
(D) inversely as the pressure drop
6- The pressure intensity of a liquid is same in all directions only when
(A) fluid is frictionless
(B) fluid is frictionless and incompressible
(C) fluid is frictionless and at rest
(D) there is no relative motion between the fluid layers adjacent to each other
7- Prandtl’s mixing length is
(A) zero at the pipe wall
(B) maximum at the pipe wall
(C) independent of shear stress
(D) dependent on viscosity of the fluid
8- A floating body is in a state of equilibrium when its
(A) metacentre is below its centre of gravity
(B) metacentre is above its centre of gravity
(C) centre of gravity is below the centre of buoyancy
(D) metacentric height is zero
9- Two pipe systems are said to be equivalent when
(A) the head loss due to the friction is same in both the systems
(B) the discharge is same in both the systems
(C) the same head loss produces the same discharge in both the systems
(D) the friction factor and effective length of both the systems are equal
10- The existence of the velocity potential indicates that
(A) the flow is irrotational
(B) the flow is rotation
(C) vorticity is zero
(D) steady
11- Surface tension explains the
(A) phenomenon of cavitation in a fluid flow
(B) spherical shape of the drop of a liquid
(C) rise of sap in a tree
(D) flow of jet of oil in an unbroken stream
12- Surface roughness
(A) hastens the transition of flow from laminar to turbulent
(B) retards the transition of flow from laminar to turbulent
(C) impedes the flow
(D) reduces the discharge
13- Which of the following number deal with the Cavitation Phenomenon?
(A) Thoma Number
(B) Euler Number
(C) Reynolds Number
(D) Weber Number
14- In open channel, maximum velocity occurs
(A) at the surface
(B) just below the surface
(C) at the mid-depth of flow
(D) near the channel bottom
15- Hagen-Poiseuille equation deals with
(A) Laminar Flow
(B) Transitional Flow
(C) Turbulent Flow
(D) Boundary Layer
16- The science which deals with the surface streams is known as
(A) Limnology
(B) Potamology
(C) Cryology
(D) Geomorphology
17- A body floating in a liquid is said to be in neutral equilibrium, if its metacentre
(A) coincides with the centre of gravity.
(B) lies above the centre of gravity.
(C) lies below the centre of gravity.
(D) lies between the centre of buoyancy and centre of gravity.
18- The mercury does not wet the glass. This is due to the property of liquid known as _______
(A) Cohesion
(B) Adhesion
(C) Viscosity
(D) Surface Tension
19- The imaginary line drawn in the fluid in such a way that the tangent to any point gives the direction of motion at that point, is known as _______
(A) Path line
(B) Stream line
(C) Steak line
(D) Potential line
20- The coefficient of discharge for an external mouthpiece depends upon
(A) Velocity of liquid
(B) Pressure of liquid
(C) Area of mouthpiece
(D) Length of mouthpiece
ANSWERS:
1-(B), 2-(C), 3-(A), 4-(C), 5-(B), 6-(D), 7-(A), 8-(B), 9-(C), 10-(A), 11-(B), 12-(A), 13-(A), 14-(B), 15-(A), 16-(B), 17-(A), 18-(D), 19-(B), 20-(D)