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 345 of 350
- A. Differential pressure gage
- B. External float gage
- C. Gage glass
- D. None of these
Explanation: A differential-pressure gauge measures liquid level from the hydrostatic pressure difference between the tank bottom and the vapour space.
Correct answer: Differential pressure gage- A. Zero
- B. Second
- C. First
- D. Third
Explanation: A U-tube manometer contains liquid inertia and restoring action, with damping from flow resistance, so its dynamic model is generally…
Correct answer: Second- A. Polarograph
- B. Photo electric cell
- C. Thermal conductivity meter
- D. Chromatograph
Explanation: Smoke density reduces the intensity of a light beam passing through the flue gas, so a photoelectric cell can detect the resulting change…
Correct answer: Photo electric cell- A. Open
- B. Both A. and B.
- C. Closed
- D. Neither A. nor B.
Explanation: For a feedback system, the characteristic equation is obtained by setting the denominator of the closed-loop transfer function to zero…
Correct answer: Closed6885. Measurement of sub-zero Celsius temperature in industry is done most commonly by __________________?
- A. Thermocouples
- B. Bi-metallic thermometers
- C. Gas thermometers
- D. Resistance thermometers
Explanation: Resistance thermometers, especially platinum RTDs, provide accurate and stable measurement over the sub-zero industrial range.
Correct answer: Resistance thermometers- A. < 1
- B. > 1
- C. 1
- D. None of these
Explanation: For a first-order system, the amplitude ratio is 1/√[1+(ωτ)²]. Thus it is less than unity for a sinusoid of nonzero frequency, because the…
Correct answer: < 1- A. Mercury in glass thermometer
- B. Resistance thermometer
- C. Thermocouple
- D. Vapor pressure thermometer
Explanation: A thermocouple provides a continuous electrical temperature signal and is rugged enough for industrial heat-exchanger service.
Correct answer: Thermocouple- A. 250
- B. 500
- C. 750
Explanation: Fibreglass insulation used around thermocouple wires is generally suitable up to about 500°C.
Correct answer: 500- A. All a, b & c
- B. Accuracy (± 1% of span)
- C. Speed of response
- D. Temperature measuring range (- 40°C to 450°C)
Explanation: Industrial bimetallic and mercury-in-glass thermometers can have broadly comparable ranges, accuracy, and response characteristics in…
Correct answer: All a, b & c- A. Low loads
- B. High loads
- C. Temperature changes
- D. Flow rate changes
Explanation: A positioning controller gives an essentially on-off output, making it suitable for switching large or high-capacity loads where fine…
Correct answer: High loads- A. Load
- B. Controlled
- C. Manipulated
- D. None of these
Explanation: The heating or cooling-fluid flow rate is adjusted by the controller to influence shell temperature, so it is the manipulated variable.
Correct answer: Manipulated- A. d
- B. d2
- C. d3
- D. d4
Explanation: For a diaphragm of fixed material and thickness, deflection strongly depends on diameter and varies approximately with the fourth power of…
Correct answer: d4- A. Closed loop values vs. open loop values
- B. A.R. vs. phase lag of second order
- C. A.R. vs. phase lag of first order
- D. Frequency response values of controllers
Explanation: A Nichols chart relates open-loop gain and phase to the resulting closed-loop performance, with closed-loop magnitude contours…
Correct answer: Closed loop values vs. open loop values- A. Helical
- B. Semi-circular
- C. Circular
- D. Spiral
Explanation: Bourdon tubes are commonly formed as C-shaped, helical, or spiral tubes, while a circular form is not a standard configuration.
Correct answer: Circular- A. Piston type meter
- B. Rotameter
- C. Orifice and tapered plug meter
- D. Magnetic flow meter
Explanation: A magnetic flow meter determines flow from the voltage induced in a conductive fluid, so it does not use a changing flow area.
Correct answer: Magnetic flow meter- A. Introducing integral control
- B. Reducing value of Kc
- C. Introducing derivative control
- D. None of the above
Explanation: Proportional-only control leaves a steady-state offset when a sustained error is needed to produce the required output.
Correct answer: Introducing integral control- A. Velocity
- B. Time
- C. (Time)-1
- D. None of these
Explanation: A time constant characterizes how quickly a system responds, and its dimension is time.
Correct answer: Time- A. Ruth
- B. Mikhailov
- C. Nyquist
- D. None of these
Explanation: The Nyquist stability method assesses closed-loop stability from the frequency response of the open-loop transfer function.
Correct answer: Nyquist- A. Speed of response
- B. Reproducibility
- C. Fidelity
- D. Static characteristics
Explanation: Fidelity is the ability of an instrument to reproduce changes in the measured variable without dynamic error.
Correct answer: Fidelity6900. Temperature measurement by optical pyrometer is done above ____________ point, which is 1063°C ?
- A. Gold
- B. Antimony
- C. Silver
- D. Nickel
Explanation: An optical pyrometer is generally used above the gold point, approximately 1063°C, where contact thermometers become unsuitable.
Correct answer: Gold