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Level Measurement Quiz

Test yourself with 15 multiple choice questions. Check your answers to get a score and an explanation for every question.

15 questionsInstant scoreExplanationsInterview practice

Level Measurement Quiz: 15 Questions

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

1. DP level measurement in an open tank needs:

Answer: Only the density and the head of liquid. DP = ρgh on the HP side; the LP side is vented to atmosphere.

2. A wet leg on the LP side usually results in:

Answer: Zero elevation (negative LRV). The wet leg head on the LP side makes the DP negative at low level.

3. A transmitter mounted below the lower tapping with liquid filled line gives:

Answer: Zero suppression (positive LRV). The extra head adds a positive offset.

4. Radar level measures:

Answer: Time of flight of microwaves. Distance = c × t ÷ 2.

5. Ultrasonic level accuracy is mainly affected by:

Answer: Temperature of the air (speed of sound). Speed of sound changes about 0.6 m/s per °C.

6. A guided wave radar is preferred over non contact radar for:

Answer: Very low dielectric liquids, foam and interfaces. Guided wave radar keeps a strong signal on the probe.

7. A displacer level transmitter works on:

Answer: Archimedes principle (buoyancy). The apparent weight of the displacer changes with buoyancy.

8. For DP level, if the liquid density increases and the transmitter is not re ranged, the reading:

Answer: Reads high. More DP for the same height: the level reads high.

9. A vibrating fork level switch is mainly used for:

Answer: Point level (high or low alarm). Forks detect presence or absence of liquid at a point.

10. The blocking (near) distance of a radar is:

Answer: The zone close to the antenna where level cannot be measured reliably. Keep maximum level below the blocking distance.

11. Interface level by DP requires:

Answer: Both tappings always covered by liquid. Both taps must be in liquid so the DP reflects the two densities.

12. A false echo map in radar is recorded:

Answer: With the tank as empty as practical. Low level exposes internals that cause false echoes.

13. Level in a horizontal cylindrical tank versus volume is:

Answer: Non linear. Volume per unit level is greatest at mid level.

14. Bubbler level systems measure:

Answer: Back pressure of gas through a dip tube. The air back pressure equals the liquid head at the tube tip.

15. A 3 m column of water creates a DP of about:

Answer: 294 mbar. 3 × 98.07 mbar ≈ 294 mbar.
0 of 15 answered
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About this Quiz

15 multiple choice questions on level measurement, 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. Only the density and the head of liquid: DP = ρgh on the HP side; the LP side is vented to atmosphere.
  2. Zero elevation (negative LRV): The wet leg head on the LP side makes the DP negative at low level.
  3. Zero suppression (positive LRV): The extra head adds a positive offset.
  4. Time of flight of microwaves: Distance = c × t ÷ 2.
  5. Temperature of the air (speed of sound): Speed of sound changes about 0.6 m/s per °C.
  6. Very low dielectric liquids, foam and interfaces: Guided wave radar keeps a strong signal on the probe.
  7. Archimedes principle (buoyancy): The apparent weight of the displacer changes with buoyancy.
  8. Reads high: More DP for the same height: the level reads high.
  9. Point level (high or low alarm): Forks detect presence or absence of liquid at a point.
  10. The zone close to the antenna where level cannot be measured reliably: Keep maximum level below the blocking distance.
  11. Both tappings always covered by liquid: Both taps must be in liquid so the DP reflects the two densities.
  12. With the tank as empty as practical: Low level exposes internals that cause false echoes.
  13. Non linear: Volume per unit level is greatest at mid level.
  14. Back pressure of gas through a dip tube: The air back pressure equals the liquid head at the tube tip.
  15. 294 mbar: 3 × 98.07 mbar ≈ 294 mbar.
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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