QUESTIONS AND ANSWERS LEVEL_INSTRUMENTATION

QUESTIONS AND ANSWERS LEVEL_INSTRUMENTATION 

1. A capacitor consists of two conductive plates separated by a dielectric. What is an example of the two plates in a capacitance level measuring device?
   1. Indictors installed on the container and a sight glass
   2. A pressure gage and a float actuated sensor
   3. The stilling well and a float ring or collar
   4. The side of the process container and an immersion electrode

 

2. When using resistance to measure level, a probe consisting of two conductive strips is inserted into a tank, and the circuit is energized. As the level of the process material rises, what forces the two strips together?
   1. Hydrostatic pressure
   2. Temperature
   3. Type of process material
   4. Gravimetric properties of the process material

 

3. How is a capacitor electrode positioned for continuous level measurement?
   1. Vertically in the process material
   2. Horizontally in the process material
   3. Vertically along the exterior of the process container
   4. Horizontally along the exterior of the process container

 

4. Which of the following best defines capacitance?
   1. The ability of a device to ground an electrical circuit
   2. The property of an electrical device that allows it to store energy
   3. The amount of energy that can be stored without destroying a circuit
   4. The property of an electrical device that allows it to resist current overload

 

5. Which of the following does NOT influence the amount of charge that can be stored in a capacitor?
   1. Size of the conductive plates
   2. Type of dielectric used
   3. Placement within the process fluid
   4. Distance between conductive plates

 

6. How is the capacitor electrode positioned for point measurement? 
   1. Vertically along the exterior of the process container
   2. Horizontally along the exterior of the process container
   3. Vertically in the process material
   4. Horizontally in the process material

 

7. Which of the following is considered an advantage of using capacitors for level measurement?
   1. There are no moving parts
   2. Unaffected by changes in temperature
   3. Inherently resistant to build up of process material on sensors
   4. Variations of process material do not affect continuous measurement

 

8. What variable must be compensated for when capacitance level measurement is employed?
   1. Resistance
   2. Temperature
   3. Pressure
   4. Density

 

9. Which of the following variables must be compensated for when capacitance level measurement is employed?

1. Resistance
2. Density
3. Temperature
4. Pressure

 

10.Which of the following is an advantage of using capacitors for level measurement?

1. Variations of process material do not affect continuous measurement
2. Unaffected by changes in temperature
3. Inherently resistant to build up of process material on sensors
4. Maintenance requirement is relatively low

 

11. The ability of a substance to conduct electricity is called:
    1. Conductivity
    2. Resistance
    3. Capacitance
    4. Dielectric

12.When using the conductivity method, what device prevents the interface from being disturbed?

1. Electrode stabilizer
2. Stilling well
3. Relay terminal
4. Dielectric

13.Which of the following is a major limitation of using the conductivity method?

1. Only continuous measurement can be performed
2. Can only be used in nonconductive process materials
3. Only point detection can be performed
4. Required maintenance is extensive

14.Which of the following devices is used to prevent false measurements?

1. Electrode stabilizer
2. Relay terminal
3. Dielectric
4. Stilling well

15.What forces the two conductive strips of a resistance probe together as the process material rises?

1. Hydrostatic force
2. Temperature increase
3. Chemical properties of the process material
4. Specific gravity of the process material

16.Before using a resistance device for level measurement, how is the base reading taken?

1. While the tank is at its maximum acceptable level and probe is energized
2. When tank is empty and probe is energized
3. While the tank is at its maximum acceptable level and probe is de-energized
4. When tank is empty and probe is de-energized

 

17. What isolates the two conductive strips of a resistance device from the process material?
    1. Isolation is not required
    2. Gold plating
    3. Plastic sheath
    4. Nonferrous tube

18. When using a resistance device, the interface height depends on the known resistance per length and:
    1. Specific gravity of the process fluid
    2. Type of process material
    3. Gravimetric properties of the conductive strips
    4. Uniform separation of wire resistor and base strip

19. Resistance devices can be used for each of the following interfaces EXCEPT:
    1. Liquid-to-liquid
    2. Liquid-to-gas
    3. Slurries
    4. Solids

21. Which of the following process materials is NOT appropriate for resistance sensing devices?
    1. Liquid-to-gas
    2. Liquid-to-liquid
    3. Slurries
    4. Solids

21. When using a resistance device in closed process applications, the pressure inside the protective sheath must be:
    1. Greater than process pressure
    2. Less than process pressure
    3. Equal to process pressure
    4. Equal to atmospheric pressure

22. When using a resistance device in closed process applications, pressure must be equalized inside and outside of the protective sheath in order to prevent:
    1. Contamination of process fluid
    2. Electrode corrosion
    3. Rupture of plastic sheath
    4. Pressurized vapor from shorting the circuit

23. What characterizes the sonic conductivity of a substance?
    1. Type of measurement method and device used
    2. Density and surface characteristics
    3. Temperature of the substance
    4. Height of the substance

24. The following are the advantages to using non-invasive ultrasonic sensors to measure level EXCEPT for:
    1. The transducer and receiver are placed in direct contact with the outside walls of the container
    2. This allows for a gap between the wall of the tank and the sensor
    3. Used for continuous and point measurement
    4. There are only a limited number of process variables to consider

25. Substances that tend to absorb sound waves are called:
    1. Dead media
    2. Live media
    3. Solid media
    4. Soft media

 

26. Sonic conductivity depends on a substance’s surface characteristics and:
    1. Weight
    2. Density
    3. Temperature
    4. Size

27. What is the minimum sound wave frequency of an ultrasonic level detection device?
    1. 10,000 cycles per second
    2. 15,000 cycles per second
    3. 20,000 cycles per second
    4. 25,000 cycles per second

28. Ultrasonic devices involve the production and reception of sound waves with a frequency of:
    1. 10,000 cycles per second
    2. 15,000 cycles per second
    3. 18,000 cycles per second
    4. 20,000 cycles per second and higher

29. How is the ultrasonic sensor probe situated for liquid-to-liquid interface measurement?
    1. Inserted into the process material at a slight angle
    2. Inserted vertically into the process material
    3. Inserted horizontally into the process material
    4. Positioned above the process material without being inserted

30. What is the purpose of installing two ultrasonic transducers and receivers in a process container?
    1. Continuous level measurement
    2. Detect high and low process levels
    3. One primary and one backup
    4. Single point monitoring

31. Which type of process interface is not suited for measurement with a single probe device?
    1. Liquid-to-liquid
    2. Liquid-to-gas
    3. Solid-to-gas
    4. Solid-to-liquid

32. Which type of ultrasonic level sensor is appropriate for use with solids?
    1. Single probe
    2. Single probe with vibrating elements
    3. Non-invasive ultrasonic sensor
    4. Two-element design

34. Continuous ultrasonic level indication devices are also known as:
    1. Sonar devices
    2. Single probe devices
    3. Dual point devices
    4. Live media
35. What is produced when an ultrasonic beam is reflected from an interface?
    1. Direct beam
    2. Echo
    3. Dead media
    4. Interface noise

35. Which of the following process material characteristics must be known in order for level to be determined with a sonar device?
    1. Salinity and volume
    2. Specific gravity and temperature
    3. Temperature and composition
    4. Volume and composition

36. What is the generic name for continuous ultrasonic level measuring devices?
    1. Single probe devices
    2. Dual point devices
    3. Live media
    4. Sonar devices

37. What type of ultrasonic device is used in applications where contact between the process materials and the sensing element cannot occur?
    1. Non-invasive probe
    2. Single probe
    3. Single probe with vibrating element
    4. Dual transducer-receiver elements

38. How are non-invasive ultrasonic level sensors mounted?
    1. In direct contact with inside wall of container
    2. In direct contact with outside wall of container
    3. Partially submerged in the process fluid
    4. Completely submerged in the process material

39. Non-invasive ultrasonic level sensors are mounted:
    1. Partially submerged in the process fluid
    2. Completely submerged in the process material
    3. In direct contact with outside wall of container
    4. In direct contact with inside wall of container

40. Which of the following devices is used in applications where contact between the process material and the sensing element cannot occur?
    1. Single probe
    2. Single probe with vibrating element
    3. Dual transducer-receiver elements
    4. Non-invasive

41. Which of the following is NOT considered an advantage of ultrasonic level measuring devices?
    1. Only consistency and specific gravity of the process material must be considered
    2. Used for continuous and point measurement
    3. There are no moving parts
    4. Contact between sensor and process liquid is not necessary

42. Each of the following are advantages of ultrasonic level measuring devices EXCEPT:
    1. Used for continuous and point measurement
    2. Only consistency and specific gravity of the process material must be considered
    3. There are no moving parts
    4. Contact between sensor and process liquid is not necessary

43. The only process variables that need to be considered when using ultrasonic measuring devices are:
    1. Temperature and specific gravity
    2. Volume and composition
    3. Temperature and consistency
    4. Salinity and volume

44. Which two process variables must be considered when employing an ultrasonic level measuring device?
    1. Temperature and specific gravity
    2. Volume and composition
    3. Salinity and volume
    4. Temperature and consistency

45. An alternative method to measuring level is the rotating paddle, which is used primarily for:
    1. Continuous level measurement of gases
    2. Continuous level measurement of solids
    3. Point level measurement of gases
    4. Point level measurement of solids

46. When would a gravimetric level measurement method be employed?
    1. Anytime a continuous measurement of the process fluid is necessary
    2. In hard to handle process situations such when the process material is turbulent
    3. Anytime a point measurement application should be employed
    4. When you are using a no mechanical means to measure level

47. The motor of a rotating paddle device typically turns the paddle at a rate of:
    1. 10 revolutions per minute
    2. 20 revolutions per minute
    3. 30 revolutions per minute
    4. 40 revolutions per minute

48.How does a rotating paddle device indicate level?

1. Paddle vibration is dampened when contact is made with a process material, which
   actuates an alarm
2. Paddle slows or stops when process material impedes its rotation, actuating an alarm
3. Electrodes in the paddle actuate an alarm when contact is made with a process material
4. Paddle emits ultrasonic beams that reflect off the surface of the process material and
   actuates an alarm

 

49. Which of the following devices is best suited for point level measurement of solids?
    1. Vibrating paddles
    2. Single probe ultrasonic device
    3. Rotating paddles
    4. Single probe vibrating element

50. The vibrating paddle device is primarily used for:
    1. Continuous level measurement of solids
    2. Continuous level measurement of gases
    3. Point level measurement of gases
    4. Point level measurement of liquids

51. Which of the following is a type of thermal sensing element?
    1. Thermistor
    2. Capacitor
    3. Resistor
    4. Potentiometer

52. What device prevents a thermistor from coming in direct contact with the process?
    1. Stilling well
    2. Thermal well
    3. Gold plating
    4. Plastic sheath

53. Thermal sensing level devices operate on the principle that:
    1. Contact between a thermal sensing device and the process material generates heat, which
       can be measured
    2. Process materials under pressure conduct heat at a constant rate
    3. Different process materials conduct heat at different rates
    4. Gases conduct heat more readily than liquids

54. How is thermistor resistance affected when the process liquid contacts a heated thermal well?
    1. Resistance remains fixed at predetermined value
    2. Resistance remains constant
    3. Resistance fluctuates until contact is broken
    4. Resistance changes as heat is conducted away

55. Somewhat continuous measurement can be attained by installing:
    1. A bank of nuclear counters
    2. Two detectors and two radiation sources >
    3. A single detector and multiple radiation sources
    4. A bank of radiation sources

56. What can be accomplished by installing a bank of nuclear counters?
    1. Multiple point measurement
    2. Somewhat continuous measurement
    3. High and low level measurement
    4. Single point measurement

57. In a nuclear level measurement device, energy loss is detected by the:
    1. Receiver probe
    2. Radiation source
    3. Radiation counter
    4. Thermal monitor

58. In a nuclear level measurement device, the presence of process material is determined by:

1. Temperature increase
2. Temperature decrease
3. Increased energy level
4. Energy loss

59. Which of the following is NOT an advantage of nuclear radiation level measuring devices?

1. Very few safety and regulatory issues
2. Can be non-invasive
3. Capable of penetrating thick process containers
4. Useful in high pressure or hazardous material applications

 

60. Each of the following are advantages of nuclear radiation level measuring devices EXCEPT:
    1. Useful in high pressure or hazardous material applications
    2. Very few safety and regulatory issues
    3. Can be non-invasive
    4. Capable of penetrating thick process containers

61. Each of the following types of level measuring devices is non-invasive EXCEPT:
    1. Ultrasonic
    2. Microwave
    3. Resistance probe
    4. Nuclear radiation

62. Which of the following level measurement devices is suited for high pressure, closed processes?
    1. Dipstick
    2. Resistance probe
    3. Rotating paddles
    4. Nuclear radiation

63. What method of level measurement is appropriate for highly agitated or turbulent processes?
    1. Gravimetric method
    2. Ultrasonic method
    3. Nuclear method
    4. Resistance method

64. The inferential measurement of level by weighing a container and its contents is also referred to as:
    1. Balance method
    2. Gravimetric method
    3. Capacitance method
    4. Resistance method

65. What method of level measurement infers the volume of one process substance in a tank based on its weight and specific gravity?
    1. Capacitance
    2. Resistance
    3. Gravimetric
    4. Ultrasonic

66. Which of the following is a limitation of the gravimetric method of inferring level?
    1. Cannot be used with turbulent processes
    2. Requires a continuous supply of electrical current
    3. Many safety and regulatory issues must be addressed
    4. Only one material may be added at a time