All Free Chemical Engineering MCQs with Answers
Every Chemical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
6,983 questions · page 201 of 350
- A. None of these
- B. Specific gravity
- C. Fanning friction factor
- D. Euler number
Explanation: Euler number, specific gravity, and Fanning friction factor are all dimensionless quantities.
Correct answer: None of these- A. Long pipe at decreasing rate
- B. Long pipe at constant rate
- C. Expanding tube at constant rate
- D. None of these
Explanation: A long pipe carrying fluid at a constant rate represents steady flow, and its constant cross-section gives uniform flow along the pipe.
Correct answer: Long pipe at constant rate- A. Weber
- B. Euler
- C. Mach
- D. Froude
Explanation: The Euler number is the ratio of pressure force to inertial force, commonly written as Eu = ΔP/(ρV²) apart from the chosen constant…
Correct answer: Euler- A. Expansion joint
- B. Coupling
- C. Flange
- D. Sleeve joint
Explanation: A sleeve joint joins underground pipe sections by fitting a sleeve over their ends and is commonly used for buried pipelines.
Correct answer: Sleeve joint- A. Is a positive displacement pump
- B. Is a centrifugal pump
- C. Is a non-positive displacement pump
- D. Can be started with delivery valve closed
Explanation: A gear pump traps and transports a fixed volume of liquid per revolution, making it a positive-displacement pump.
Correct answer: Is a positive displacement pump4006. For a particle settling in water at its terminal settling velocity, which of the following is true ?
- A. Buoyancy = weight + drag
- B. Weight = buoyancy + drag
- C. Drag = buoyancy + weight
- D. Drag = weight
Explanation: At terminal settling velocity, acceleration is zero and the downward weight is balanced by the upward buoyancy and drag forces.
Correct answer: Weight = buoyancy + drag- A. d
- B. d2
- C. d2.5
- D. d4
Explanation: In fully turbulent flow, the friction factor is treated as approximately independent of Reynolds number.
Correct answer: d2.5- A. Turbine
- B. None of these
- C. Diffuser
- D. Propeller
Explanation: Propeller pumps have an axial-flow configuration, with fluid entering and leaving mainly parallel to the pump shaft.
Correct answer: Propeller- A. ε = ε0 + α.t
- B. ε = ε0 + α.t2
- C. ε = ε0 + α.t3
- D. ε = ε0 + α.t4
Explanation: Colebrook and White represented surface deterioration as a linear increase in roughness with time, so ε equals the initial roughness plus…
Correct answer: ε = ε0 + α.t- A. 0.5
- B. 1
- C. 1.5
- D. 2
Explanation: For the most economical trapezoidal channel, the hydraulic radius is half the flow depth, R = y/2.
Correct answer: 2- A. Data insufficient to predict pressure drop
- B. Decrease
- C. Remain same
- D. Increase
Explanation: Both flows are laminar, so pressure drop at fixed velocity is proportional to viscosity.
Correct answer: Increase- A. Mach number
- B. Weber number
- C. Euler number
- D. Reynolds number
Explanation: The Mach number, Ma = V/c, compares fluid velocity with the speed of sound and therefore indicates the importance of compressibility…
Correct answer: Mach number- A. 4.4 KPa
- B. 2.94 KPa
- C. 3.7 KPa
- D. None of these
Explanation: At incipient fluidisation, the pressure drop balances the effective weight of the particles: ΔP = (ρs − ρf)(1 − ε)Lg.
Correct answer: 4.4 KPa- A. Flow rate
- B. Both 'a' & 'b'
- C. Mean velocity
- D. Neither 'a' nor 'b'
Explanation: For a partially filled circular channel, the hydraulic radius reaches its maximum at approximately Dm = 0.3D.
Correct answer: Mean velocity- A. Varies parabolically across the cross-section
- B. Remains constant over the cross-section
- C. Is zero at the wall and increases linearly to the centre
- D. Is zero at the centre and varies linearly with the radius
Explanation: A force balance on a cylindrical fluid core gives shear stress proportional to the radial distance from the centre, τ = (−dp/dz)r/2.
Correct answer: Is zero at the centre and varies linearly with the radius- A. Reciprocating
- B. Diaphragm
- C. Gear
- D. Centrifugal
Explanation: A diaphragm pump handles thick, viscous and solids-containing slurries because its flexible diaphragm provides positive displacement…
Correct answer: Diaphragm- A. Fluid velocity decreases to zero
- B. Total energy decreases
- C. Flow pressure approaches its vapor pressure at the prevailing temperature
- D. Both A. and B.
Explanation: Cavitation begins when the local absolute pressure falls to or below the liquid vapour pressure at the operating temperature, causing…
Correct answer: Flow pressure approaches its vapor pressure at the prevailing temperature- A. Suitably designing the pump
- B. Maintaining suction head lower than the vapour pressure
- C. Maintaining suction head = developed head
- D. Maintaining the suction head sufficiently greater than the vapour pressure
Explanation: Cavitation is avoided by ensuring the pressure head at the pump suction remains sufficiently above the liquid vapour-pressure head…
Correct answer: Maintaining the suction head sufficiently greater than the vapour pressure- A. Dilatant
- B. None of these
- C. Pseudo plastic
- D. Bingham plastic
Explanation: Sewage sludge commonly behaves as a Bingham plastic: it requires a yield stress before flowing and then shows an approximately linear…
Correct answer: Bingham plastic- A. Inertial forces control and viscous forces are unimportant
- B. Viscous forces predominate
- C. Inertial forces are unimportant and viscous forces control
- D. None of these
Explanation: A high Reynolds number means inertial forces are large relative to viscous forces, so flow behaviour is principally controlled by inertia…
Correct answer: Inertial forces control and viscous forces are unimportant