Level Measurement Multiple Choice Questions

1. Which of the following devices are used for a level to force conversion?
a) Load cell
b) Membrane
c) Diaphragm
d) Voltmeter
Answer: Load cell
2. If the specific gravity of the liquid inside the vessel increases, what aspects of the transmitter’s calibration will we need to change in order to maintain accurate liquid level measurement?
a) We will need to change the transmitter’s LRV and linearity
b) We will need to change the transmitter’s linearity and span
c) We will need to change the transmitter’s LRV and URV
d) We will need to change the transmitter’s linearity and zero
Answer : We will need to change the transmitter’s LRV and URV
3. Suppose a storage vessel holds a liquid of unpredictable density. Identify which level measurement technology will not maintain accurate measurement of liquid height in the vessel as the liquid density changes
a) Differential pressure transmitter
b) Guided-wave radar
c) Ultrasonic
d) Float and tape
Answer : Differential pressure transmitter
4. What will happen if the float becomes lighter?
a) Density variations becomes more important
b) Density variations becomes less important
c) System becomes less efficient
d) None of the mentioned
Answer: Density variations becomes less important
5. The main advantage of a “dip tube” or “bubbler” system for level measurement is that
a) It isolates the pressure transmitter from the process fluid
b) It always elevates and never suppresses the calibration range
c) It is less expensive to operate than a direct-connected transmitter
d) It compensates for changes in liquid density
Answer : It isolates the pressure transmitter from the process fluid
6. In closed container type level measuring system, pressure at top of container is due to ______________
a) Vacuum pressure
b) Vapor pressure
c) Liquid pressure
d) Atmospheric pressure
Answer: Vapor pressure
7. A displacer-type level transmitter has a cylindrical displacer 30 inches long and 2.5 inches in diameter. When fully submerged in a petroleum fuel (Gf = 0.82), how much buoyant force will the displacer generate?
a) 5.320 pounds
b) 6.488 pounds
c) 4.363 pounds
d) 17.45 pounds
Answer : 4.363 pounds
8. Which of the following conversions take place in float element?
a) Level to force
b) Level to voltage
c) Level to displacement
d) None of the mentioned
 Answer: Level to displacement
9. A d/p cell used to measure liquid level has a “suppressed zero.” This means
a) The transmitter is located above the 0% liquid level mark
b) The transmitter uses filter circuits to suppress noise to a zero level
c) The liquid is less dense than water
d) The transmitter is located below the 0% liquid level mark
Answer : The transmitter is located below the 0% liquid level mark
10. Which of the following level measurement technologies cannot be adapted to measure solid (powder) level in a vessel?
a) Displacer
b) Float and tape
c) Radar
d) Ultrasonic
Answer : Displacer
11. Which of the following is correct for a level to force conversions?
a) Liquid at constant density distribution
b) Liquid with different density distribution
c) Level difference should be gradual
d) Liquid should be highly viscous
Answer: Liquid at constant density distribution
12. A guided-wave radar transmitter is able to measure liquid interface levels based on differences of between the two liquids.
a) Ionization potential
b) Dielectric constant
c) Speed of light
d) Temperature
Answer : Dielectric constant
13. In ______________ system, float whose weight greater than liquid to be displaced is used.
a) Inverse float system
b) Displacer system
c) Magnifying float system
d) None of the mentioned
Answer: Displacer system
14. Calculate the hydrostatic pressure at the bottom of a vessel holding 17 vertical feet of liquid with a density of 55 lb/ft3.
a) 33.8 PSI
b) 8.36 PSI
c) 21.2 PSI
d) 6.49 PSI
Answer : 6.49 PSI
15. Which of the following represents pressure of a liquid column with constant density?
a) ϱgh
b) ϱh
c) ϱg
d) None of the mentioned
Answer: ϱgh
16. Which of the following represents correct relation for pressure in manometer type level measuring system?
a) (ϱmhm – ϱy)g
b) (ϱm – ϱy)g
c) (ϱmhm – ϱ)g
d) ϱmhm – ϱy
Answer: (ϱmhm – ϱy)g
17. Diaphragm element is used for a level to pressure conversion.
a) True
b) False
Answer: True
18. For float element, uniformity of density is important.
a) True
b) False
Answer: False
19. Load cell devices are used for a level to force conversion
a) True
b) False
Answer: True
20. Density variations becomes less important if the float becomes lighter
a) True
b) False
Answer: True