Instrumentation Articles

125 QUESTIONS & ANSWERS TEMPERATURE INSTRUMENTATION_ENGINEERING

1. Which of the following devices responds to temperature by producing a Action or movement?

1.   Bimetallic thermometer
2.   Thermocouple
3.   Resistance temperature detector
4.   Radiation pyrometer

2. One definition of temperature is based on the theory that: All molecules are in motion; motion is sensed as heat and measured as

1.  Temperature
2.   All matter contains heat
3.   Atomic particles are hot
4.   Radiation creates heat

3.  Definitions of temperature are based on:

1.    Molecular stability and energy non-transference
2.   Molecular motion and thermal energy transfer
3.   Molecular motion and molecular transfer
4.   Molecular stability and molecular cohesion

4. The four most commonly used scales to measure temperature are the:

1.  Fahrenheit, Celsius, Kelvin, and Newton scales
2.   Fahrenheit, Celsius, Galileo, and Rankine scales
3.   Fahrenheit, Celsius, Kelvin, and Rankine scales
4.   Fahrenheit, Galileo, Rankin, and Kelvin scales

5. The two general classes of temperature measuring devices are:

1.  Thermocouples and bulbs
2.  Bulb thermometers and temperature sensors
3.  Closed and open sensors and thermometers
4.  Temperature sensors and absolute thermometers

6. Two of the most common temperature sensors are

1. Thermocouples and resistance temperature detectors
2. Thermal transmitters and resistive couplers
3. Thermocouples and reactive detectors
4. Thermal transmitters and resistance temperature detectors

7. Temperature sensors are classified according to their

1.  Mounting
2.  Construction
3.  Application
4.  Configuration

8. Two examples of absolute thermometers are the:

1.   Resistance temperature detectors and the thermocouples
2.    Reactive detectors and thermocouples
3.   Radiation pyrometers and gas bulb thermometers
4.  Resistance temperature detectors and thermocouples

9. Mechanical temperature devices respond to temperature by producing

1.    An electrical signal that causes a mechanical action
2.    Light signals that radiate to a sensor
3.   A mechanical action or electrical signal
4.   A mechanical action or movement

10. What type of measurement error may result from surface mounted sensors?

•  Stem loss error
• Thermal shunting error
•  Radiation error
•  Line-of-sight error

11. What type of temperature measurement error may occur with high velocity fluids?

•   Response time error
•  Heat transfer lag error
•  Surface mounted sensor error
•  Frictional heating error

12. Stem loss errors can be reduced by using a:

•  Longer sensor
•  Cylindricalsensor
•  Shorter sensor
•   Sensor with a bulbous head

13. Thermal shunting can occur with surface mounted sensors if the lead wires are:

•    Too long
•   Not insulated correctly
•   Too short
•   Wrapped around a pipe

14. When temperature sensors are installed in gases, measurement errors can be caused by:

•  Reactance
•  Inductance
•  Radiation
•  Resistance

15. One way to solve the problem of radiation when measuring the temperature of gases is to install the sensor so that there is no direct line of sight between:

•   The sensor and the substance being measured that may be at a different temperature
•  The substance being measured and the sensor control
•  The sensor and the materials that may be at the same temperature
•  Materials that may be at a different temperature from the substance being measured and the sensor

16. Frictional heating errors may occur in:

•   High velocity fluids
•   Low velocity fluids
•   Thin fluids
•   Thick fluids

17. Kinetic energy is converted to heat when:

• Sensor shields are used
• The fluid impacts the tip of the sensor
• Fluid flow increases
• Friction between shield and sensor is minimized

18. To insure accuracy on surface mounted sensors, the sensor must be installed:

• Vertically in the center of the wall
• To the wall of the pipe
• With a tight interface between the sensor and the wall
• With the sensor in the center of the pipe

19. What is a major consideration when the temperature sensor is used for safety, process control, or data acquisition?

• The process being measured
• Material from which the sensor is made
• Sensor position
• Heat transfer lag

20. Which component of the liquid-in-glass thermometer serves to contain the fluid at high temperatures?

• Glass chamber
• Capillary tube
• Expansion chamber
• Contraction chamber

21. An identifying characteristic of the complete immersion thermometer is that it:

• Is immersed to the height of the fluid column
• Is the most accurate liquid-in-glass thermometer
• Has no immersion ring
• Is inserted to a fixed point

22. The type of thermometer that indicates temperature on a scale as the helix winds or unwinds is known as

• Gas-filled system thermometer
• Mercury filled system thermometer
• Vapor system thermometer
• Bimetallic thermometer

23. The components of a liquid-in-glass thermometer include:

• The bulb, the stem, and the capillary tube
• The stem, the bulb, and the capsule
• The ball, the shaft, and the piping
• The stem, the liquid cell, and the capillary tube

24. The component of a liquid-in-glass thermometer that increases the volume to contain fluid at low temperatures is called the:

• Capillary tube
• Contraction chamber
• Bulb
• Expansion chamber

25. The expansion chamber is located:

• Between the bulb and the capillary tube
• At the bottom of the thermometer
• Above the main capillary
• Between the bulb and the scale

26. The operation of a liquid-in-glass thermometer depends on:

• Viscosity of the fluid used
• The material or process that is being measured
• Composition of the bulb
• The coefficient of the liquid expansion being greater than that of  the bulb

27. The thermometer that is inserted to a fixed point indicated by the immersion ring is the:

• Partial immersion thermometer
• Total immersion thermometer
• Complete immersion thermometer
• Liquid-in-glass thermometer

28. The thermometer that is designed to be immersed to the height of the fluid column is the:

• Partial immersion thermometer
• Total immersion thermometer
• Complete immersion thermometer
• Liquid-in-glass thermometer

29. The thermometer that is designed to be totally submerged in the fluid to be measured is the:

• Partial immersion thermometer
• Total immersion thermometer
• Complete immersion thermometer
• Liquid-in-glass thermometer

30. The thermometer that is the most accurate of the three liquid-in-glass thermometers is the:

• Partial immersion thermometer
• Total immersion thermometer
• Non-immersion thermometer
• Complete immersion thermometer

 

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

QUESTIONS AND ANSWERS LEVEL INSTRUMENTATION

What is the definition for the term level as it applies to process measurement?

1. Level refers to the amount of space occupied by an object or fluid in a tank. It can also be used
   to express the capacity of a container
2. Level is defined as the amount of force applied by a pressurized fluid on each unit area of its
   container
3. Level is defined as the position between phases, where the phases liquid/gas, solid/gas, or immiscible liquid/liquid.
4. Level refers to the measure of the internal molecular activity of a substance

What should you consider when selecting a level measurement device?

3. Physical properties of the process materials only
4. Chemical properties of the process materials only
5. Both the physical and chemical properties of the process materials
6. A point measurement system or a continuous measurement system only

What are the two types of level measurement?

1. Continuous and point
2. Point and intermediate
3. Intermediate and point
4. Range and specific point

What is the definition of level as it applies to the measurement of process variables?

1. The horizontal distance between the interface and one or more specific points
2. The vertical distance between the interface and one or more specific points
3. The horizontal distance between the interface and the flow over point
4. The total distance gained or lost by the process material gage

Two important types of level measurement are:

1. Point and intermediate
2. Intermediate and point
3. Continuous and point
4. Range and specific point

Level, as it applies to the measurement of process variables, is defined as:

1. The horizontal distance between the interface and one or more specific points
2. The horizontal distance between the interface and the flow over point
3. The total distance gained or lost by the process material gage
4. The vertical distance between the interface and one or more specific points

Which of the following objectives must be defined when selecting a level measuring instrument?

1. Remote versus local
2. Standard versus defined
3. Open versus sealed
4. Primary versus secondary

What are two ways a level measuring device uses to detect the location of the interface?

1. Estimated and gaged
2. Direct and inferential
3. Indirect and direct
4. Inferential and estimated

Before selecting a level measuring device, you must:

1. Obtain instrument documentation
2. Outline the entire process
3. Define measurement objectives
4. Examine surrounding environment

Which properties must be considered when selecting a level measuring device?

1. Characteristics of the environment surrounding the process only
2. Chemical properties of the process material only
3. Physical properties of the process material only
4. Both physical and chemical properties of the process material

Which measuring device would you use if you were measuring a highly viscous processed liquid?

1. Sight glass
2. Plastic tube
3. Float
4. Dipstick

In a float device which component indicates the level of the substance on the scale plate?

1. Float ring
2. Collar magnet
3. Switch magnet
4. Follower

Which of the following level measuring devices is weighted at one end to ensure vertical insertion?

1. Steel tape
2. Sight glass
3. Dipstick
4. Float

What is considered the simplest direct method of measuring process level?

1. Audible
2. Visual
3. Mechanical
4. Electrical

Which of the following devices consists of a length of rigid material with graduated lines?

1. Steel tape
2. Sight glass
3. Dipstick
4. Float

The simplest direct method of measuring process level is by:

1. Audible alert
2. Mechanical detection
3. Electrical detection and signal
4. Sight

Crude level measurement of granular solids or highly viscous process liquids can be obtained with a:

1. Dipstick
2. Sight glass
3. Float
4. Steel tape

Which level measuring device can be used for crude level measurement of granular solids or highly viscous process liquids?

1. Steel tape
2. Dipstick
3. Sight glass
4. Float

Each of the following are limitations to the dipstick or steel tape devices EXCEPT:

1. Cannot be used in processes that require pressure or temperature control
2. Cannot be used for toxic or corrosive gases
3. Cannot be used with process materials other than liquids
4. Requires an open process container for insertion

Which measuring device would you use if you were measuring the level container of granular solids?

1. Steel tape
2. Float
3. Sight glass
4. Dipstick

Which level measuring device operates on the principle that liquid seeks the same level when equal Pressure is exerted on the surface of two connected columns?

1. Sight glass
2. Dip gage
3. Float cylinder
4. Float tube

Which level measuring device is used in closed, low-pressure systems?

1. Dip gage
2. Sight glass
3. Steel tape
4. Dipstick

A device installed with service valves that allow it to be isolated from the process is called a:

1. Dip tube
2. Float tube
3. Sight glass
4. Ball-check tube

What type of device operates on the principle that liquid seeks the same level when equal pressure is exerted on the surfaces of two connected columns?

1. Steel tape
2. Dipstick
3. Float
4. Sight glass

Using a sight glass to measure level involves a risk of:

1. Glass breakage
2. Inaccurate level readings
3. Overheating
4. Process product evaporation

Sight glass devices should be installed:

1. In a hidden location
2. Where risk of breakage is small
3. At a 45 degree angle for ease of viewing
4. At or near the top of the process container

What risk is involved when using a sight glass to measure level in a process container?

1. Inaccurate level readings
2. Overheating
3. Glass breakage
4. Process product evaporation