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FLUID MECHANICS mcqs
mcqs of fluid mechanics , top mcqs of fluid mechanics

 
   

 

ANS KEY IS AT THE END

 

III. FLUID MECHANICS

 
1. Viscosity in fluids refers to

 
(a) the density of a fluid  
(b) the compressibility of a fluid
(c) tangential force exerted on solid surface by the flowing fluid
(d) normal forces exerted on solid surface by the flowing fluid






2. Viscosity is a measure of the resistance of a fluid that is being deformed by either shear stress or tensile stress. Which of the following is more viscous?

 
a)    air                            b)  honey
c)   ketch up                   d)  water

 
3. Which law states that the pressure change in a confined incompressible fluid is transmitted equally in all directions throughout the fluid and to the walls of the container?



(a) Ohm’s law        (b) Pascal’s law
(c) Kirchoff’s law   (d) Newton’s law

 
4. All liquid surfaces tend to contract. This phenomenon is due to

(a) viscosity                (b) diffusion                    
(c) density                    (d) surface tension     
 
                                                                                                                                      

                                                                                              
5. Which principle states that for an ideal fluid, an increase in the speed of fluid occurs stimultaneously with adecrease in fluid’s pressure or P.E.?

(a) Bernulli’s principle     (b) Archimedes’ principle
(c) both of the above       (d) none of the above

 
6. The nib of fountain pen is split to convey ink down the nib by the phenomenon of

(a) Adhesion    (b) Cohesion
(c) Osmosis      (d) Capillary

 
7. The buoyancy depends upon the

(a) depth to which the body is immersed
 (b) shape of the body
(c) mass of body
(d) mass of the liquid displaced




 
8. Which principle states that buoyant force on a submerged object is equal to the weight of the fluid displaced by the object

(a) Bernoulli’s principle     (b) Archimedes’ law
(c) both of the above         (d) none of the above

 
9. Bernoulli’s equation includes a special case of

(a) Archimede’s law   (b) Hooke’s law
(c) Torrcelli’s law       (d) Newton’s law
 

 
10. The venturi-meter is an instrument used for measuring

(a) the viscosity of a fluid                   

(b) the specific gravity of a fluid
(c) the flow speed of a liquid          

(d) the compressibility of a fluid

11. Turbulent flow of a fluid occurs when the Reynold number is a above about

(a) 1000               (b) 2000
(c) 3000               (d) 4000

 
12. Fluid flows a laminar for Reynold numbers up to

(a) 500            (b) 1000
(c) 2000          (d) 4000

 
13. For the Bernoulli’s theorem to the applicable, the fluid flow should be

(a) rotational and compressible
(b) irrational and incompressible
(c) irrotational (non-trubulent) and compressible
(d) irrotational and incompressible

 
14. The ratio of the speed of an object moving through air to the speed of sound is called

(a) Reynold number          (b) Mach number
(c) Avogadro’s number     (d) Feigenbaum number

 
15. Surface tension of a liquid may be defined as

(a) heat energy per unit area
(b) potential energy per unit area
(c) surface energy per unit area
(d) kinetic energy per unit area

 
16. Powder clings to the face due to

(a) compression      (b) capillary action
(c) cohesion             (d) adhesion

 
17. The ideal fluid model is based on four   assumptions

(a) non viscous, incompressible,  steady flow, non-turbulent
(b)  viscous , compressible, steady flow, turbulent
(c) non viscous, compressible, steady flow, turbulent
(d) non viscous, incompressible, steady flow, turbulent

 
18. A beaker is full of water with an ice piece floating. The ice piece has a lead piece in it. When ice cube melts them

(a) water overflows                   (b) level falls
(c) level remains unchanged         (d) none of these
 

 
19. The velocity at which laminar (steady) flow changes to turbulent (eddy) flow is called

(a) terminal velocity      (b) escape velocity
(c) critical velocity          (d) uniform velocity
 
 

 
 
20. The Magnus effect is equivalent to
 

(a) Bernoulli’s theorem    (b) Archimedes’ principle
(c) Pascal’s law                   (d) none of these
 

ANSWERS

1. c  2. c  3. b  4. d
5. a  6. d  7. d  8. b
9. c  10. c   11. c  12. c
13. d  14.  b  15. c  16. d
17. a  18. b  19. c   20. a

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BY M S KHATTAK

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