The value of friction factor ‘f’ for smooth pipes for Reynolds number 106 is approximately equal to________________?

Related Mcqs:

1. For laminar flow in circular pipes, the Darcy’s friction factor f is equal to_________________?

   A. 16/Re
   B. 32/ Re
   C. 64/ Re
   D. none of the above where R,, is Reynolds number

2. For hydro-dynamically smooth boundary, the friction coefficient for turbulent flow is_______________?

   A. constant
   B. dependent only on Reynolds number
   C. a function of Reynolds number and relative roughness
   D. dependent on relative roughness only

3. For laminar flow in a pipe of circular cross-section, the Darcy’s friction factor f is________________?

   A. directly proportional to Reynolds number and independent of pipe wall roughness
   B. directly proportional to pipe wall roughness and independent of Reynolds number
   C. inversely proportional to Reynolds number and indpendent of pipe wall roughness
   D. inversely proportional to Reynolds number and directly proportional to pipe wall roughness

4. For a sphere of radius 15 cm moving with a uniform velocity of 2 m/sec through a liquid of specific gravity 0.9 and dynamic viscosity 0.8 poise, the Reynolds number will be_________________?

   A. 300
   B. 337.5
   C. 600
   D. 675

5. Least possible value of correction factor for________________?

   1. kinetic energy is zero
   2. kinetic energy is 1
   3. momentum is zero
   4. momentum is 1

   The correct statements are?

   A. (1) and (3)
   B. (2) and (3)
   C. (1) and (4)
   D. (2) and (4)

6. In which of the following the friction drag is generally larger than pressure drag?

   A. a circular disc or plate held normal to flow
   B. a sphere
   C. a cylinder
   D. an airfoil

7. The horse power transmitted through a pipe is maximum when the ratio of loss of head due to friction and total head supplied is________________?

   A. 1/3
   B. 1/4
   C. 1/2
   D. 2/3

8. Two pipes of same length and diameters d and 2d respectively are connected in series. The diameter of an equivalent pipe of same length is________________?

   A. less than d
   B. between d and 1.5 d
   C. between 1.5 d and 2d
   D. greater than 2d

9. If the elevation of hydraulic grade line at the junction of three pipes is above the elevation of reservoirs B and C and below reservoir A, then the direction of flow will be___________________?

   A. from reservoir A to reservoirs B and C
   B. from reservoir B to reservoirs C and A
   C. from reservoir C to reservoirs A and B
   D. unpredictable

10. The major loss of energy in long pipes is due to_______________?

    A. sudden enlargement
    B. sudden contraction
    C. gradual contraction or enlargement
    D. friction