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 202 of 350
- A. Discharge pressure
- B. Back flow of fluid in the event of stoppage of pump
- C. Flow of liquid during operation of the pump
- D. All A., B. and C.
Explanation: The discharge check valve closes when the pump stops, preventing liquid from flowing backward through the pump and protecting the impeller…
Correct answer: Back flow of fluid in the event of stoppage of pump- A. Speed
- B. Impeller diameter
- C. Both A. and B.
- D. Neither A. nor B.
Explanation: Centrifugal-pump head varies with impeller speed and diameter; approximately, head is proportional to the square of speed and impeller…
Correct answer: Both A. and B.4023. Pump used for the transportation of molten sodium in a fast breader reactor is a/an __________ pump?
- A. Electromagnetic
- B. Plunger
- C. Reciprocating
- D. Gear
Explanation: Molten sodium in a fast breeder reactor can be transported using an electromagnetic pump, which moves the electrically conducting liquid…
Correct answer: Electromagnetic- A. D = 1840 N/H0.5
- B. D = 1840 H0.5/N
- C. H = 1840 D0.5/N
- D. D = 1840 H/N
Explanation: For a centrifugal pump, the developed head is related to the impeller peripheral speed, which is proportional to DN; hence D varies as…
Correct answer: D = 1840 H0.5/N- A. 1
- B. 0.5
- C. 2
- D. 1.5
Explanation: In the Stokes-law regime, terminal velocity is proportional to the square of particle diameter, so vₜ ∝ dₚ² and n = 2.
Correct answer: 2- A. Either A. or B.; depends on the viscosity of the fluid
- B. Less
- C. Equal
- D. More
Explanation: A globe valve forces the fluid through a tortuous, repeatedly changing path, whereas a fully open gate valve offers a comparatively…
Correct answer: More4027. With increase in the shear rate, the apparent viscosity of pseudo-plastic fluids__________________?
- A. Decreases
- B. Increases
- C. Remain same
- D. May increase or decrease; depends on the magnitude of shear rate
Explanation: A pseudoplastic fluid is shear-thinning: increasing shear rate reduces its apparent viscosity.
Correct answer: Decreases- A. 2v2/gc
- B. ρv2/gc
- C. v2/2gc
- D. ρ.v2/2gc
Explanation: Velocity head is kinetic energy per unit weight, obtained by dividing kinetic energy per unit mass by g; in engineering-unit notation it…
Correct answer: v2/2gc4029. Mass velocity is independent of temperature & pressure, when the flow is______________________?
- A. Unsteady through unchanged cross-section
- B. Steady through changing cross-section
- C. Unsteady and the cross-section is changed
- D. Steady and the cross-section is unchanged
Explanation: For steady flow, the mass flow rate is constant, and with an unchanged area the mass velocity remains constant throughout the passage.
Correct answer: Steady and the cross-section is unchanged- A. 1
- B. 10
- C. 40
- D. 70
Explanation: A Venturimeter recovers most of the pressure in its diffuser, so its permanent loss is small, commonly about 10% of the pressure drop in…
Correct answer: 104031. The uniformity of a gas fluidised bed depends upon the _______________ of the solid particles?
- A. Size
- B. Both A. and B.
- C. Surface properties
- D. Neither A. nor B.
Explanation: Uniform fluidisation is strongly affected by particle size and by surface characteristics such as roughness and cohesiveness.
Correct answer: Both A. and B.4032. Most of the centrifugal pumps used in chemical plants are usually ____________________ driven?
- A. Steam
- B. Diesel engine
- C. Electric motor
- D. Gas turbine
Explanation: Electric motors are compact, reliable, and readily controlled, so they commonly drive centrifugal pumps in chemical plants.
Correct answer: Electric motor- A. Gate
- B. Globe
- C. Needle
- D. Butterfly
Explanation: Butterfly valves are lightweight quarter-turn valves and can be fitted with actuators for remote operation, making them common…
Correct answer: Butterfly- A. Piston
- B. Vane
- C. Centrifugal
- D. Plunger
Explanation: A vane pump handles liquids of moderate viscosity smoothly and gives nearly continuous flow, making it suitable for medium-viscosity…
Correct answer: Vane- A. Atmospheric pressure
- B. Pressure difference between two points
- C. Sub-atmospheric pressure
- D. None of these
Explanation: A differential manometer connects two pressure points and indicates their pressure difference through the difference in liquid levels.
Correct answer: Pressure difference between two points- A. Varies parabolically across the section
- B. Is constant over the entire cross-section
- C. Is zero at the plates and increases linearly to the mid-plane
- D. None of these
Explanation: Fully developed laminar flow between fixed parallel plates has a parabolic velocity profile, with zero velocity at each stationary plate…
Correct answer: Varies parabolically across the section- A. 0.03
- B. 0.3
- C. 3
- D. 10
Explanation: For gases and liquids, compressibility effects are usually negligible when the Mach number is below about 0.3.
Correct answer: 0.3- A. At the wall
- B. At d/4 from the wall
- C. At the centre
- D. At d/8 from the wall
Explanation: In fully developed laminar pipe flow, shear stress increases linearly from zero at the centre to its maximum at the wall.
Correct answer: At the wall- A. Temperature
- B. Both A. & B.
- C. Pressure
- D. Neither A. nor B.
Explanation: Mass velocity is mass flow rate per unit cross-sectional area, G = m/A.
Correct answer: Both A. & B.- A. HB/2 (H + B)
- B. HB/(H + B)
- C. 2HB/(H + B)
- D. 4HB/(H + B)
Explanation: Equivalent diameter is defined as 4A/P, where A = BH and the wetted perimeter is P = 2(B + H).
Correct answer: 2HB/(H + B)