571. With increase in molecular weight of the gas, the head developed by a centrifugal compressor will
Decrease
Increase
Remain same
Unpredictable
✅ The correct answer is option A.
Fluid Mechanics MCQs
572. Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newton’s law of viscosity. (II) Newton’s second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to boundary. (V) Fluid cannot penetrate a boundary.
I, II, III
II, III, V
I, II, V
II, IV, V
✅ The correct answer is option B.
573. A differential pressure cell is used for
Measuring small pressure difference in gases
Measuring small pressure difference in liquids
Remote recording of pressure difference
Measuring the difference of the impact & the static pressure
✅ The correct answer is option C.
574. Which of the following exemplifies a three dimensional fluid flow ?
Fluid flow at the inlet to a nozzle
Fluid flow between parallel plates
Viscous fluid flow between converging plates
None of these
✅ The correct answer is option A.
575. Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter ‘d’?
At the centre
At d/4 from the wall
At the wall
At d/8 from the wall
✅ The correct answer is option C.
576. A 2″ gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is
Δp
< Δp
> Δp
Δp²
✅ The correct answer is option C.
577. A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is
5
14.1
56.22
28.2
✅ The correct answer is option D.
578. The simple pitot tube measures the __________ pressure.
Static
Dynamic
Total
None of these
✅ The correct answer is option C.
579. Friction factor for a hydraulically smooth pipe at NRe = 2100 is f₁. If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe, will
Increase
Decrease
Remain unchanged
Increase or decrease depending on the pipe material
✅ The correct answer is option A.
580. The velocity profile for turbulent flow through a closed conduit is
Logarithmic
Parabolic
Hyperbolic
Linear
✅ The correct answer is option A.