81. The major loss of energy in long pipes is due to_______________?
A. sudden enlargement
B. sudden contraction
C. gradual contraction or enlargement
D. friction
✅ The correct answer is option D.
Fluid Mechanics MCQs
82. The discharge over a broad crested weir is maximum when the depth of flow is_______________?
A. H/3
B. H/2
C. 2 H/5
D. 2 H/3
✅ The correct answer is option D.
83. 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
✅ The correct answer is option D.
84. An open tank contains 1 m deep water with 50 cm depth of oil of specific gravity 0.8 above it. The intensity of pressure at the bottom of tank will be________________?
A. 4 kN/m2
B. 10 kN/m2
C. 12 kN/m2
D. 14 kN/m2
✅ The correct answer is option D.
85. 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
✅ The correct answer is option C.
86. 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
✅ The correct answer is option C.
87. Coefficient of velocity of venturimeter_________________?
A. is independent of Reynolds number
B. decreases with higher Reynolds number
C. is equal to the coefficient of discharge of venturimeter
D. none of the above
✅ The correct answer is option C.
88. The unit of kinematic viscosity is_______________?
A. gm/cm-sec2
B. dyne-sec/cm2
C. gm/cm2-sec
D. cm2/sec
✅ The correct answer is option D.
89. Which of the following is an incorrect statement ?
A. Coefficient of contraction of a venturimeter is unity
B. Flow nozzle is cheaper than venturimeter but has higher energy loss
C. Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined
D. None of the above statement is correct.
✅ The correct answer is option D.