Fluid Mechanics Objective Questions (MCQ) part-01

Fluid Mechanics Objective Questions (MCQ)

1. If Dynamic Viscosity of a Fluid = 0.6 poise & Specific Gravity = 0.6 , then Kinematic Viscosity of that Fluid in Stokes will be…? 

1. 0.5

2. 0.75

3. 1.0

4. 1.25

We know Kinematic Viscosity = Dynamic Viscosity / Specific Gravity 

  Kinematic Viscosity = 0.6 / 0.6 

 Kinematic Viscosity =  1.0 stokes 

   Kinematic viscosity has SI units of m2 s−1 

Fluid Mechanics

2. The Intensity of Pressure developed by Surface tension of    0.07 N/m in a Droplet of water of 0.07 mm diameter is 

1. 0.9 N/cm2

2. 1.0 N/cm2

3. 0.4 N/cm2

4. 40 N/cm2   

We know, The Intensity of Pressure developed in a Droplet of water

           = 2 * Surface tension / Radius 

            = 2 * 0.07 * 10-2 / { (0.07/2) *10-1} 

                                 = 0.4 N/cm2

As Surface tension is in N/m, convert  in N/cm, 

Also diameter = 2 * radius & also in N/mm, convert in N/cm.

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3. One Kilo-Pascal is equivalent to 

1. 1000 N/mm2

2. 1000 N/cm2

3. 1000 N/m2

4. 4000 N/mm2                                  

⇒ Pressure = force / area = N / m2

In general, Pressure is expressed in terms of N/m-2

 known as Pascal. 

⇒ 1 Pascal = Newton meter-2 =1 Nm-2

⇒  1 k Pa=103 Nm-2= 1000 Nm-2

⇒ 1 M Pa = 106 Nm-2 

In case of KG, Pascal 

   

K Pa	Kg/m2
1	101.975
10	1019.75
100	10197.5

4. Pressure of  300 kpa is equivalent to a head of X meters of carbon tetra-chloride of relative density 1.69, where X =  

1. 18.12

2. 19.12

3. 18.23

4. 19.23 

Here, X = Pressure /{ relative density * gravity }

               = 300/ { 1.69 * 9.81}

                       = 19.23 m 

5) The Theoretical Value of Coefficient of Contraction of Sharped Edged Orifice is…

1. 0.71

2. 0.81

3. 0.611

4. 0.51 

Sharped Edged Orifice = ⊼/ (⊼ + 2)

= 0.611

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