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 203 of 350
- A. Constant
- B. Variable
- C. Both A. & B.
- D. Neither A. nor B.
Explanation: A rotameter operates with a nearly constant pressure drop across its float, while the float position changes until the upward fluid force…
Correct answer: Constant- A. Perfect gases only
- B. All compressible fluids
- C. Adiabatic unsteady flow of gases
- D. Isothermal flow of gases
Explanation: The general energy equation includes internal, pressure, kinetic and potential-energy terms, so it is applicable to compressible fluids…
Correct answer: All compressible fluids- A. Hyperbola
- B. Semi-circle
- C. Parabola
- D. Semi-ellipse
Explanation: For fully developed laminar flow of a Newtonian fluid in a circular pipe, the velocity profile follows v = v_max[1 − (r/R)^2].
Correct answer: Parabola- A. Turbine type impeller
- B. None of these
- C. Rotating vaned volute
- D. Vaned diffusion casing
Explanation: A centrifugal pump is termed a turbine pump when it uses a diffuser or vaned diffusion casing to convert part of the impeller's velocity…
Correct answer: Vaned diffusion casing- A. Higher than
- B. Lower than
- C. Equal to
- D. None of these
Explanation: Cavitation begins when the local liquid pressure falls to or below the vapour pressure at the operating temperature.
Correct answer: Higher than- A. Speed of impeller, diameter of impeller & viscosity
- B. None of these
- C. Density of fluid, viscosity of fluid & impeller dia only
- D. Density & viscosity of fluid only
Explanation: Mixing power depends on impeller speed, impeller diameter, fluid density and viscosity.
Correct answer: None of these4047. Which of the following properties of a fluid is responsible for offering resistance to shear ?
- A. Surface tension
- B. Specific gravity
- C. Viscosity
- D. All A., B., and C.
Explanation: Viscosity measures a fluid's resistance to the relative motion of adjacent layers, hence its resistance to shear.
Correct answer: Viscosity- A. Axial
- B. Radial
- C. Mixed
- D. None of these
Explanation: Low-specific-speed centrifugal pumps generally have radial flow, intermediate values indicate mixed flow, and high values indicate axial…
Correct answer: Axial- A. Reciprocating
- B. Centrifugal
- C. Gear
- D. Diaphragm
Explanation: A centrifugal pump must first have its casing and suction line filled with liquid because it cannot effectively create suction while…
Correct answer: Centrifugal- A. Power of the pump
- B. Nature of the liquid being pumped
- C. Angle of the vanes and the speed of the tip of the impeller
- D. Vapour pressure of the liquid
Explanation: The pump head follows from the Euler turbomachinery relation and is strongly governed by impeller peripheral speed and vane angles, which…
Correct answer: Angle of the vanes and the speed of the tip of the impeller- A. Q/2
- B. Q/4
- C. Q/16
- D. Q/8
Explanation: For laminar flow through a capillary, the Hagen-Poiseuille equation gives Q proportional to r^4 for fixed pressure drop and length.
Correct answer: Q/16- A. A circular
- B. A large
- C. A small
- D. Any convenient
Explanation: A stream tube is formed by a bundle of streamlines, and its cross-sectional shape need not be circular or fixed to a particular size.
Correct answer: Any convenient- A. Rotational and compressible
- B. Rotational and incompressible
- C. Irrotational and compressible
- D. Irrotational and incompressible
Explanation: With u = -xy^2 and v = 2x^2y, the divergence at the stated point is -y^2 + 2x^2 = -1 + 1 = 0, so the flow is incompressible.
Correct answer: Rotational and compressible- A. Require less space
- B. Have quieter operation
- C. All A., B. and C.
- D. Have lower operating costs
Explanation: Centrifugal compressors are compact, produce less noise and vibration, and generally have lower maintenance and operating costs than…
Correct answer: All A., B. and C.- A. Reynolds
- B. Weber
- C. Euler
- D. Mach
Explanation: The Mach number is the ratio of inertial forces to elastic forces, and it also equals the flow velocity divided by the speed of sound.
Correct answer: Mach- A. 0.42
- B. 0.62
- C. 0.82
- D. 0.98
Explanation: For a sharp-edged orifice, contraction and nonideal velocity effects combine to give a discharge coefficient of about 0.61 to 0.62.
Correct answer: 0.62- A. Static submergence
- B. Net positive suction head (NPSH)
- C. Cavitation sensitivity
- D. Priming
Explanation: NPSH is the suction pressure head, expressed relative to the liquid vapour-pressure head, available to prevent cavitation at a pump…
Correct answer: Net positive suction head (NPSH)- A. Cohesion
- B. Adhesion
- C. Both A. & B.
- D. Neither A. nor B.
Explanation: Capillary rise requires adhesion between the liquid and tube wall, while cohesion helps maintain the continuous liquid column.
Correct answer: Both A. & B.- A. Elevation
- B. Neither A. nor B.
- C. Both A. & B.
- D. Velocity
Explanation: In a horizontal contraction, a reduction in pressure head is mainly accompanied by an increase in velocity head because the smaller area…
Correct answer: Velocity- A. Rotary
- B. Reciprocating
- C. Axial
- D. None of these
Explanation: Rotary compressors are suited to relatively low-pressure service with large discharge rates and provide steadier flow than reciprocating…
Correct answer: Rotary