Free Fluid Flow Operations MCQs with Answers
909 Fluid Flow Operations MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Non-sticky & non-corrosive nature
- B. Low co-efficient of thermal expansion
- C. Low viscosity & surface tension
- D. High vapour pressure
Explanation: A manometric liquid should have low vapour pressure so that it does not vaporise or introduce significant measurement error.
Correct answer: High vapour pressure- A. Head varies as the square of speed
- B. Its capacity varies directly as the square of speed
- C. Horsepower input varies as the square of speed
- D. Head varies as the speed
Explanation: With impeller diameter fixed, the pump affinity laws give capacity proportional to N, head proportional to N², and input power…
Correct answer: Head varies as the square of speed- A. Reciprocating
- B. Centrifugal
- C. Volute
- D. Gear
Explanation: For a given duty, centrifugal pumps generally have the lowest maintenance cost because they contain few wearing parts and have no…
Correct answer: Centrifugal- A. Rotameter
- B. Venturimeter
- C. Orificemeter
- D. Pitot tube
Explanation: A Pitot tube is especially convenient for large-diameter pipes because it requires only a small probe and measures local velocity without…
Correct answer: Pitot tube- A. The S.I. unit of dynamic viscosity
- B. The S.I. unit of kinematic viscosity
- C. Equivalent to one poise
- D. Equivalent to one stoke
Explanation: Dynamic viscosity has SI units of Pa·s, which are equivalent to N·s/m².
Correct answer: The S.I. unit of dynamic viscosity- A. ML-2
- B. MT-2
- C. MLT-2
- D. ML-2T
Explanation: Surface tension is force per unit length, so its dimensions are (MLT⁻²)/L = MT⁻². The dimension MLT⁻² represents force, not surface tension.
Correct answer: MT-2- A. N
- B. N/m
- C. N/m2
- D. N/m3
Explanation: Bulk modulus is a pressure divided by volumetric strain, and strain is dimensionless.
Correct answer: N/m2- A. 1/x
- B. 1/√x
- C. x
- D. √x
Explanation: For laminar flow over a flat plate, boundary-layer thickness varies as δ ∝ √x because the layer grows downstream by momentum diffusion.
Correct answer: √x- A. Parabola (vertex being at the opening)
- B. Hyperbola
- C. Horizontal straight line
- D. Zig-zag path (which is geometrically undefined)
Explanation: The jet has horizontal velocity as it leaves the opening and vertical acceleration due to gravity.
Correct answer: Parabola (vertex being at the opening)- A. 25
- B. 250-300
- C. 100
- D. 1000
Explanation: A single-stage centrifugal pump commonly develops a maximum head of roughly 250 to 300 ft.
Correct answer: 250-300- A. Less than
- B. Equal to
- C. Always greater than
- D. Not necessarily greater than
Explanation: In hindered settling, nearby particles and the surrounding particle-rich fluid increase resistance to motion compared with free settling.
Correct answer: Always greater than- A. Diaphragm
- B. Piston
- C. Turbine
- D. None of these
Explanation: A turbine pump is designed with impeller flow having both radial and axial components, which is the defining feature of mixed flow.
Correct answer: Turbine- A. Increasing the impeller speed and the volute area
- B. Increasing the number of vanes in the impeller
- C. Either of A., B. or C.
- D. Mounting of two or more impellers in series on a single shaft
Explanation: Placing two or more impellers in series adds their heads while keeping the flow rate approximately the same, making multistaging the…
Correct answer: Mounting of two or more impellers in series on a single shaft- A. Develops high pressure
- B. Increase in thrust
- C. Develops noise
- D. Decrease in effect
Explanation: Cavitation commonly causes efficiency loss, noise, vibration, thrust fluctuations, and mechanical damage, but it does not produce a…
Correct answer: Develops high pressure- A. Linear
- B. Logarithmic
- C. Hyperbolic
- D. Parabolic
Explanation: In the turbulent boundary layer of a smooth pipe, the central velocity profile is represented by the logarithmic law, relating velocity to…
Correct answer: Logarithmic- A. Equal to
- B. Less than
- C. More than
- D. Either A. or B.
Explanation: The float must be denser than the liquid so that its weight can overcome buoyancy and allow it to settle, while the upward flow drag…
Correct answer: More than- A. Re <> 1, accelerating flow
- B. Re << 1, decelerating flow
- C. Re >>1, decelerating flow
Explanation: Boundary-layer separation requires a sufficiently large Reynolds number and an adverse pressure gradient, represented here by decelerating…
Correct answer: Re >>1, decelerating flow- A. Partially filled pipeline
- B. Pipe
- C. Open channel
- D. River
Explanation: A completely filled pipe carries pressure flow because the fluid is confined and its motion is driven by a pressure gradient.
Correct answer: Pipe- A. Tall narrow vessel
- B. Deep bed of solids
- C. Shallow beds of solids and proper choice of particle size
- D. Very large particles
Explanation: Slugging is reduced by using a shallow bed and selecting particles that fluidise uniformly, which limits the growth of large gas pockets.
Correct answer: Shallow beds of solids and proper choice of particle size- A. Disk
- B. Skin
- C. None of these
- D. Form
Explanation: Wakes form behind an immersed body when the flow separates, producing pressure or form drag.
Correct answer: Form