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 252 of 350
- A. CPA > CPB
- B. CPA < CPB
- C. kA < 0.5 kB
- D. kA >2 kB
Explanation: At steady state the same heat flux passes through both plates, so the temperature drop is proportional to thickness divided by…
Correct answer: kA < 0.5 kB- A. Re and Pr
- B. Re and Gr
- C. Pr and Gr
- D. Re and Sc
Explanation: For forced convection, the Nusselt number is commonly correlated using Reynolds number for the flow regime and Prandtl number for the…
Correct answer: Re and Pr- A. In low range of temperature differences
- B. In high range of temperature differences
- C. Because of its low cost
- D. To prevent corrosion of the tube bundles
Explanation: A floating tube bundle allows the tubes to expand and contract independently of the shell, so it is preferred when the temperature…
Correct answer: In high range of temperature differences- A. Medium
- B. Temperature
- C. None of these
- D. Surface
Explanation: The Stefan-Boltzmann constant is a universal physical constant, with a fixed value of approximately 5.67 × 10⁻⁸ W/m²·K⁴.
Correct answer: None of these- A. Occupies smaller space
- B. Is more economical
- C. Is easy to operate and maintain
- D. All A., B. and C.
Explanation: Shell-and-tube exchangers are suitable for large areas because they provide a relatively compact arrangement, reasonable cost, and…
Correct answer: All A., B. and C.- A. > 10
- B. 10
- C. < 10
- D. Either B. or C., depends on the mass of the body
Explanation: Under Newton’s law of cooling, the cooling rate decreases as the body approaches its surroundings’ temperature.
Correct answer: > 105027. Electro-magnetic spectrum range, which is important for radiation varies from _____________ microns?
- A. 0.5 to 50
- B. 1 to 100
- C. 10 to 100
- D. 100 to 1000
Explanation: Most engineering heat-transfer radiation lies roughly within the infrared region, commonly taken as about 0.5 to 50 micrometres for this…
Correct answer: 0.5 to 50- A. Condense the steam flowing in the pipeline
- B. Remove water resulting from partial condensation of steam
- C. Stop the supply of steam
- D. None of these
Explanation: A steam trap automatically discharges condensate formed when steam loses heat while retaining live steam in the pipeline.
Correct answer: Remove water resulting from partial condensation of steam5029. LMTD for counter-flow and parallel flow heat exchanger will be the same, when the_________________?
- A. None of these
- B. Outlet temperature of both the hot and cold fluid are same
- C. Outlet temperature of hot fluid is less than the outlet temperature of the cold fluid
- D. Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid)
Explanation: When one fluid condenses, its temperature remains essentially constant, so the terminal temperature differences are the same…
Correct answer: Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid)- A. Remove non-condensable gases
- B. Purge the condenser
- C. Facilitate easy cleaning of tubes
- D. None of these
Explanation: Vent pipes release air and other non-condensable gases from the condenser, since these gases reduce the effective condensing area and…
Correct answer: Remove non-condensable gases- A. Lower tube side pressure drop
- B. Higher tube side heat transfer co-efficient
- C. Lower shell side pressure drop
- D. Higher shell side heat transfer co-efficient
Explanation: In a 1-2 exchanger, the fluid makes two tube passes, approximately doubling its velocity compared with a 1-1 exchanger.
Correct answer: Higher tube side heat transfer co-efficient- A. Von-Karman
- B. Reynolds
- C. Prandtl
- D. Colburn
Explanation: The correction factor involving 5(Npr − 1)√(f/2) accounts for the difference between momentum and heat diffusivity in the Prandtl analogy.
Correct answer: Prandtl- A. Scaling
- B. Salty
- C. Corrosive
- D. Highly viscous
Explanation: Open-pan evaporators have simple, accessible heating surfaces and can handle highly viscous solutions that circulate poorly in compact…
Correct answer: Highly viscous- A. Convection
- B. Conduction
- C. Radiation
- D. Both A. & C.
Explanation: When warm and cold liquids are mixed, bulk fluid motion carries energy from one portion to another, so convection is the dominant mode.
Correct answer: Convection- A. 2
- B. 20.8
- C. 20.2
- D. 20.5
Explanation: Adding a second pass approximately doubles the air velocity. Since the air-side film coefficient varies roughly as velocity to the 0.8…
Correct answer: 20.85036. It is not preferable to use superheated steam in evaporators, because of its very_________________?
- A. High temperature
- B. High pressure
- C. None of these
- D. Low film co-efficient
Explanation: Superheated steam must first be desuperheated before condensation begins, and heat transfer from superheated steam has a much lower film…
Correct answer: Low film co-efficient- A. Double pipe
- B. U-tube
- C. Fixed tube
- D. Floating head
Explanation: A double-pipe heat exchanger is commonly used for chilling oil during dewaxing because it provides a simple arrangement suitable for…
Correct answer: Double pipe- A. Forced convection
- B. None of these
- C. Monochromatic radiation
- D. Steady state conduction
Explanation: A heat-transfer process whose rate changes with time is called unsteady-state or transient heat transfer.
Correct answer: None of these- A. 165.4
- B. 167.5
- C. 172.5
- D. 175
Explanation: The total thermal resistance per unit area is 0.10/0.05 + 0.20/0.10 + 1/20 = 4.05 m²·°C/W.
Correct answer: 165.4- A. At a particular temperature
- B. For circular bodies
- C. None of these
- D. Under thermal equilibrium
Explanation: Kirchhoff’s law of thermal radiation states that absorptivity equals emissivity when a body is in thermal equilibrium with its…
Correct answer: Under thermal equilibrium