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Flow Meter MCQ Test

Test yourself with 20 multiple choice questions. Check your answers to get a score and an explanation for every question.

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Flow Meter MCQ Test: 20 Questions

Choose one answer for each question, then press Check answers. Explanations appear after checking.

1. Flow through an orifice plate is proportional to:

Answer: The square root of DP. From Bernoulli, DP is proportional to velocity squared, so flow is proportional to √DP. Learn more: Square Root Extraction

2. At 25 % of DP span, an orifice meter shows what % of maximum flow?

Answer: 50 %. √0.25 = 0.5, so 50 % flow. Learn more: Square Root Extraction

3. Beta ratio of an orifice is:

Answer: Bore diameter ÷ pipe internal diameter. β = d ÷ D. Learn more: Beta Ratio

4. Which side of an orifice plate faces upstream?

Answer: The sharp square edge. The sharp edge faces the flow; any bevel is downstream. Learn more: Orifice Plate

5. A magnetic flow meter cannot measure:

Answer: Hydrocarbon oil. Oil is not conductive enough for Faraday law measurement. Learn more: Electromagnetic Flow Meter
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6. A coriolis meter directly measures:

Answer: Mass flow and density. Tube twist gives mass flow; tube frequency gives density. Learn more: Coriolis Flow Meter

7. Vortex shedding frequency is proportional to:

Answer: Flow velocity. f = St × v ÷ d, with St nearly constant. Learn more: Vortex Flow Meter

8. Pipe flow is usually turbulent when Reynolds number is above about:

Answer: 4000. Above about 4000 flow is turbulent; below about 2000 to 2300 laminar. Learn more: Reynolds Number

9. A K factor of 50 pulses per litre at 250 Hz gives:

Answer: 5 L/s. Q = f ÷ K = 250 ÷ 50 = 5 L/s. Learn more: K Factor

10. Meter factor is defined as:

Answer: Prover volume ÷ meter indicated volume. MF corrects the indicated volume to the true prover volume. Learn more: Meter Factor
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11. Turndown ratio of a flow meter is:

Answer: Maximum ÷ minimum measurable flow. It shows the range over which stated accuracy applies. Learn more: Turndown Ratio

12. Why do DP flow loops need a low flow cutoff?

Answer: Near zero the square root amplifies noise into false flow. Small DP noise becomes large flow at the steep start of the √ curve. Learn more: Low Flow Cutoff

13. Normal cubic metres (Nm³) commonly refer to:

Answer: 0 °C and 1.01325 bar a. Normal conditions are often 0 °C and 101.325 kPa; always state the basis. Learn more: Standard Volume Flow

14. Gas law calculations must use:

Answer: Absolute pressure and temperature in kelvin. Gas laws work only with absolute values. Learn more: Standard Volume Flow

15. A venturi tube is chosen over an orifice mainly for:

Answer: Low permanent pressure loss. Its diverging cone recovers most of the DP. Learn more: Venturi Tube
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16. Expansibility factor ε is equal to 1 for:

Answer: Liquids. Liquids are almost incompressible. Learn more: Expansibility Factor

17. Which meter usually needs no upstream straight pipe?

Answer: Coriolis. Coriolis meters are largely insensitive to velocity profile. Learn more: Straight Pipe Run

18. A Doppler ultrasonic meter needs:

Answer: Particles or bubbles in the liquid. It measures the frequency shift of sound reflected by particles. Learn more: Ultrasonic Flow Meter

19. In laminar flow the average velocity is what fraction of centreline velocity?

Answer: One half. The laminar profile is parabolic, so average = ½ maximum. Learn more: Laminar Flow

20. Pressure and temperature compensation of DP gas flow enters the equation:

Answer: Under the square root. qm ∝ √(DP × ρ), and ρ ∝ p ÷ (Z T). Learn more: Pressure and Temperature Compensation
0 of 20 answered
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About this Quiz

20 multiple choice questions on flow meter mcq test, the kind asked in instrumentation interviews, technician exams and plant training. Each answer comes with a short explanation, so the quiz works as a revision sheet too.

Show answer key
  1. The square root of DP: From Bernoulli, DP is proportional to velocity squared, so flow is proportional to √DP. Learn more: Square Root Extraction
  2. 50 %: √0.25 = 0.5, so 50 % flow. Learn more: Square Root Extraction
  3. Bore diameter ÷ pipe internal diameter: β = d ÷ D. Learn more: Beta Ratio
  4. The sharp square edge: The sharp edge faces the flow; any bevel is downstream. Learn more: Orifice Plate
  5. Hydrocarbon oil: Oil is not conductive enough for Faraday law measurement. Learn more: Electromagnetic Flow Meter
  6. Mass flow and density: Tube twist gives mass flow; tube frequency gives density. Learn more: Coriolis Flow Meter
  7. Flow velocity: f = St × v ÷ d, with St nearly constant. Learn more: Vortex Flow Meter
  8. 4000: Above about 4000 flow is turbulent; below about 2000 to 2300 laminar. Learn more: Reynolds Number
  9. 5 L/s: Q = f ÷ K = 250 ÷ 50 = 5 L/s. Learn more: K Factor
  10. Prover volume ÷ meter indicated volume: MF corrects the indicated volume to the true prover volume. Learn more: Meter Factor
  11. Maximum ÷ minimum measurable flow: It shows the range over which stated accuracy applies. Learn more: Turndown Ratio
  12. Near zero the square root amplifies noise into false flow: Small DP noise becomes large flow at the steep start of the √ curve. Learn more: Low Flow Cutoff
  13. 0 °C and 1.01325 bar a: Normal conditions are often 0 °C and 101.325 kPa; always state the basis. Learn more: Standard Volume Flow
  14. Absolute pressure and temperature in kelvin: Gas laws work only with absolute values. Learn more: Standard Volume Flow
  15. Low permanent pressure loss: Its diverging cone recovers most of the DP. Learn more: Venturi Tube
  16. Liquids: Liquids are almost incompressible. Learn more: Expansibility Factor
  17. Coriolis: Coriolis meters are largely insensitive to velocity profile. Learn more: Straight Pipe Run
  18. Particles or bubbles in the liquid: It measures the frequency shift of sound reflected by particles. Learn more: Ultrasonic Flow Meter
  19. One half: The laminar profile is parabolic, so average = ½ maximum. Learn more: Laminar Flow
  20. Under the square root: qm ∝ √(DP × ρ), and ρ ∝ p ÷ (Z T). Learn more: Pressure and Temperature Compensation
Tip: take the quiz before an interview, note the questions you missed and read the linked article for those topics.
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Frequently Asked Questions

Is this quiz free?

Yes. No sign up is needed and you can retake it as often as you like.

Are the answers explained?

Yes. After you check your answers, each question shows the correct answer and a short explanation.

Where can I find more questions?

See the Interview Q&A section of instrumentationblog.in and the linked article below.

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