111. The equivalent diameter for pressure drop calculation for a duct of square cross-section is given by(where, x = each side of the square duct)
x
πx
2x
x/2
✅ The correct answer is option A.
Fluid Mechanics MCQs
112. A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape.
Circular
Rectangular
Triangular
Trapezoidal
✅ The correct answer is option A.
113. The distribution of shear stress in a stream of fluid in a circular tube is
Linear with radius for turbulent flow only
Linear with radius for laminar flow only
Linear with radius for both laminar & turbulent flow
Parabolic with radius for both laminar & turbulent flow
✅ The correct answer is option C.
114. The temperature in isentropic flow
Does not depend on Mach number
Depends on Mach number only
Cannot drop and then increase again downstream
None of these
✅ The correct answer is option B.
115. A special type of liquid transporting device is the diffuser pump, in which __________ are minimised.
Bearing losses
Disk friction
Shock losses
Cavitation
✅ The correct answer is option C.
116. If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is
Same in both the tubes
Greater in 1 mm dia tube
Greater in 0.5 mm dia tube
Zero in both the tubes
✅ The correct answer is option C.
117. Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft.
40
34
8
37
✅ The correct answer is option C.
118. Choking in case of pipe flow means that a
Specified mass flow rate can not be achieved
Valve is closed in the line
Restriction in flow cross-section area occurs
None of these
✅ The correct answer is option A.
119. The ratio of the wall drag to the form drag in the Stoke’s law range (for motion of spherical particles in a stationary fluid) is
0.5
1
2
0.33
✅ The correct answer is option C.
120. Speed of sound in an ideal gas depends on its
Temperature
Pressure
Specific volume
None of these
✅ The correct answer is option A.