641. The fluid property, due to which, mercury does not wet the glass is
Surface tension
Viscosity
Cohesion
Adhesion
✅ The correct answer is option A.
Fluid Mechanics MCQs
642. Which of the following denotes the effect of compressibility in fluid flow?
Weber number
Mach number
Euler number
Reynolds number
✅ The correct answer is option B.
643. With increasing flow rate, the hydraulic efficiency of a centrifugal pump
Monotonically decreases
Decreases and then increases
Remains constant
Increases and then decreases
✅ The correct answer is option A.
644. The most economical flow control valve for use with large diameter pipes is a
Butterfly valve
Globe valve
Needle valve
None of these
✅ The correct answer is option A.
645. Viscosity of water is about __________ times that of air at room temperature.
15
55
155
1050
✅ The correct answer is option B.
646. Pick out the correct statement pertaining to the flow through a converging-diverging tube.
The value of Mach number is always unity at the throat
No shock wave develops in the tube when the Mach number at exit is greater than unity
Throughout the converging portion of the tube, the density increases in the downstream direction
None of these
✅ The correct answer is option B.
647. Pascal’s law is valid, only when the fluid is
Frictionless and at rest
At rest
At rest and when the frictionless fluid is in motion
None of these
✅ The correct answer is option B.
648. The nominal size of a hose pipe is specified by its
I.D.
O.D.
Thickness
None of these
✅ The correct answer is option A.
649. In case of a __________ the energy of flow is considerably decreased downstream of the machine.
Blower
Turbine
Centrifugal pump
Centrifugal fan
✅ The correct answer is option B.
650. For turbulent flow of an incompressible fluid through a pipe, the flow rate Q is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent ‘n’ is
1
0
< 1
> 1
✅ The correct answer is option C.