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 344 of 350
- A. Bright sunshine period
- B. None of these
- C. Diffuse radiation
- D. Beam radiation
Explanation: A pyrheliometer is designed with a narrow field of view to measure direct solar radiation, also called beam or normal-incidence radiation.
Correct answer: Beam radiation- A. Low loads
- B. Temperature changes
- C. Flow rate changes
- D. None of these
Explanation: On-off control is simple but causes cycling around the set point, so it is generally suitable for low-load processes where this variation…
Correct answer: Low loads- A. Pirani
- B. Mcleod
- C. Thermocouple
- D. None of these
Explanation: A pressure of 0.0001 absolute psi is an extremely high vacuum, about 0.005 torr.
Correct answer: Mcleod- A. Chromel-alumel
- B. Iron-constantan
- C. Platinum-platinum + rhodium
- D. Either A., B. or C.
Explanation: A platinum-platinum-rhodium Type S thermocouple produces approximately 5.5 mV at 600°C.
Correct answer: Platinum-platinum + rhodium- A. Nickel
- B. Invar
- C. Chromel
- D. Brass
Explanation: Brass has a linear expansion coefficient of roughly 19 × 10⁻⁶ per °C, higher than nickel and chromel, while invar has an exceptionally low…
Correct answer: Brass- A. Bellows
- B. U-tube
- C. Bourdon tube
- D. Diaphragm
Explanation: Bellows, diaphragms and Bourdon tubes are elastic mechanical elements that deform under pressure.
Correct answer: U-tube- A. Oxygen
- B. Carbon dioxide
- C. Carbon monoxide
- D. Sulphur dioxide
Explanation: A thermal-conductivity cell detects changes in gas composition from the difference in thermal conductivity between the sample and a…
Correct answer: Carbon dioxide- A. Parabolic
- B. Non-linear
- C. Linear
- D. Hyperbolic
Explanation: Over its normal operating range, the difference in expansion of the two bonded metals produces a deflection that is approximately…
Correct answer: Linear- A. 2/s2
- B. 4/s2
- C. 2/s3
- D. 4/s3
Explanation: Using L{tⁿ} = n!/sⁿ, L{2t²} equals 2(2!)/s³ = 4/s³. The power of s increases with the power of time, so 4/s² is the common distractor.
Correct answer: 4/s3- A. Open
- B. Closed
- C. Either A. or B.
- D. Neither A. nor B.
Explanation: The Bode method plots magnitude and phase of the open-loop loop-transfer function, usually G(s)H(s), to assess closed-loop stability…
Correct answer: Open- A. Has a non-zero slope at the origin
- B. Has a damped oscillatory characteristics
- C. Is overdamped
- D. Is unstable
Explanation: The characteristic equation has natural frequency √3 and damping ratio 1/√3, which is less than 1.
Correct answer: Has a damped oscillatory characteristics- A. 1/(S2 + 2)
- B. 1/(S2 - 2S + 3)
- C. 1/(S2 + 2S + 2)
- D. exp (-20 S)/(S2 + 2S - 1)
Explanation: A continuous system is stable when all poles lie in the left half of the s-plane.
Correct answer: 1/(S2 + 2S + 2)6873. What is the dynamic error in a critically damped second order instrument for a ramp input (At) ?
- A. 2 AT
- B. 0.5 AT
- C. √(AT)
- D. 1.5 AT
Explanation: For a critically damped second-order instrument subjected to a ramp input At, the steady dynamic error is twice the instrument time…
Correct answer: 2 AT- A. Chromel-alumel
- B. Iron-constantan
- C. Platinum-rhodium
- D. Platinum-platinum + rhodium
Explanation: An iron-constantan thermocouple, type J, produces approximately 22 mV at 400°C with a 0°C reference.
Correct answer: Iron-constantan- A. 20
- B. -20
- C. 10
- D. -10
Explanation: For an amplitude ratio, decibels are calculated as 20 log₁₀(ratio). Thus 20 log₁₀(0.1) = 20(-1) = −20 dB, with the negative sign…
Correct answer: -20- A. eTS
- B. None of these
- C. 1/(Ts + 1)
- D. e-TS
Explanation: A pure transportation delay T shifts a signal in time without changing its shape, and its Laplace-domain transfer function is e^(−Ts).
Correct answer: e-TS- A. 8, 0.6, 0.08
- B. 12, 0.6, 0.12
- C. 8, 0.6, 0.12
- D. 12, 0.4, 0.08
Explanation: For the conservative largest-error case, each uncertain process parameter is taken at its upper 20% limit: gain 10(1.2) = 12, time…
Correct answer: 12, 0.6, 0.126878. Paramagnetism method is not used for the composition determination of ______________ in gases?
- A. Oxygen
- B. Carbon dioxide
- C. Oxides of nitrogen
- D. Any of these
Explanation: Paramagnetic gas analysis is suitable for oxygen and nitrogen oxides because they exhibit paramagnetism.
Correct answer: Carbon dioxide- A. (T1S/(T2S + 1)
- B. (T1S + 1)/(T2S + 1)
- C. e-ηS
- D. (T1S + 1)/(T2S
Explanation: A pure time delay has transfer function e^(-τs), whose magnitude remains unity while its phase is -ωτ, becoming more negative linearly…
Correct answer: e-ηS- A. Kilo volts
- B. Micro volts
- C. Volts
- D. Milli volts
Explanation: Thermocouples generate a small thermoelectric voltage, normally measured in millivolts.
Correct answer: Milli volts