Pulp & Paper Questions and Answers – Sensors

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This set of Pulp and Paper Multiple Choice Questions and Answers (MCQs) focuses on “Sensors”.

1. A __________ for a given process must have at least one sensor, the controller, and a control element to which the results are applied.
a) Control loop
b) Kraft loop
c) Automatic loop
d) Pausing loop
View Answer

Answer: a
Explanation: The automatic control is where a machine or electronic circuit is the control as opposed to a human being is the control loop. The controller that decides what’s to be done with the information that is collected, and a control element to which the results are applied.
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2. A good example of automatic control is electric heating of a house in a cold environment, a process where a single variable is controlled.
a) True
b) False
View Answer

Answer: a
Explanation: When the temperature drops below the set point a switch (controller) is closed and the heater (control element) comes on. When the temperature rises above the set point, the switch opens and the heater is turned off.

3. This is __________ feedback loop because the desired result is determined and the information fed back to the controller for appropriate action. This system is also known as __________ control loop.
a) 1i process
b) 2i process
c) 3i process
d) 4i process
View Answer

Answer: b
Explanation: A feedback loop is a term commonly utilized in economics to indicate to a situation where part of the output of a situation is utilized for new input. An example of a positive feedback loop would be one where success feeds success.

4. The difference between the actual value and the set point is known as the __________ The controller reads the __________ and makes a decision.
a) Sensor
b) Top
c) Point
d) Error
View Answer

Answer: d
Explanation: The action taken could be very simple to very complicated, depending on the system and the size of the acceptable error. The statistics error refers to the diff. b/w the value which has been computed and the correct value.
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5. The __________ is a device which converts a change in a parameter to a change in a electric or pneumatic signal.
a) Sensor
b) Top
c) Point
d) Error
View Answer

Answer: a
Explanation: It’s a type of transducer which is a device that changes a signal from one form to another form, such as a change in light to a change in voltage or a change in voltage to a change in current.

6. A transfer function relates the value of the parameter to be measured with the output of the __________
a) Sensor
b) Top
c) Point
d) Error
View Answer

Answer: a
Explanation: Typically it is a representation in terms of spatial or temporal frequency, of the relation b/w the input and output of a linear time-invariant system with zero initial conditions and zero-point equilibrium. With optical imaging devices, for example it is the Fourier transform of the point spread function i.e., the intensity distribution cautilized by a point object in the field of view.

7. The __________ of a sensor is a measure of how the sensor responds to an actual change as a function of time. For example, all thermocouples have mass.
a) Size
b) Material
c) Time response
d) Durability
View Answer

Answer: c
Explanation: The order of a control system is determined by the power of sensor in the denominator of its transfer function If the power of sensor in the denominator of transfer function of a control system is 2, then the system is said to be second-order control system.
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8. The __________ at one temperature is immersed in a liq. of a different temperature, the output of the __ would change with time until it finally gives a reading that is around its normal error.
a) Thermocouple
b) Photoconductors
c) Photovoltaic
d) Piezoelectric
View Answer

Answer: a
Explanation: A thermocouple is an electrical device consisting of 2 different conductors forming electrical junctions at differing temperature It produces a temperature-dependent voltage as a result of the thermoelectric effect, and this voltage could be interpreted to measure temperature

9. __________ utilise a thin band of a material that becomes conductive when exposed to light of a minimum frequency.
a) Thermocouple
b) Photoconductors
c) Photovoltaic
d) Piezoelectric
View Answer

Answer: b
Explanation: It’s an optical and electrical phenomenon in which a material becomes more electrically conductive because of the absorption of electromagnetic radiation such as visible light or gamma radiation. Whenever light is absorbed by a material such as a semiconductor, the number of free electrons and electron holes inc. and raises its electrical conductivity.

10. ____________ cells produce a voltage and current that are a function of the light level incident to them. These have time constants on the order of 1 to 100 µs.
a) Thermocouple
b) Photoconductors
c) Photovoltaic
d) Piezoelectric
View Answer

Answer: c
Explanation: Photovoltaics (P.V.) covers the conversion of light into electricity utilizing semiconducting materials that manifests the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. For very less levels of light utilized in liq. scintillation counters to determine radioactivity photomultiplier tubes are utilized.

Sanfoundry Global Education & Learning Series – Pulp and Paper.
To practice all areas of Pulp and Paper, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn