Instrumentation Transducers

Resistive Transducers

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is correct for thermistors?
Positive temperature coefficient of resistance
Negative temperature coefficient of resistance
Unpredictable temperature coefficient
None of the mentioned
Explanation:
For thermistors as temperature increase, resistance decreases.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Thermistors may be in wire form.
True
False
Explanation:
Due to high brittleness thermistors cannot be formed into wire type. Hence they are shaped into bead form.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
What is the relation of temperature coefficient of resistivity on the coefficient of thermal expansion in RTD?
Higher
Lower
Equal
None of the mentioned
Explanation:
It is used to provide a considerable change in resistance when exposed to temperature.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
What will happen to resistance, if the length of the conductor is increased?
Decreases
No change
Increases
Doubles
Explanation:
As length of conductor increases, resistance increases according to expression R = (ϱl)/A.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which of the following can be used to measure using thermistors?
Very low
In-between 100Ω and 1MΩ
Greater than 1MΩ
None of the mentioned
Explanation:
Thermistor at 200c can be used to measure resistance values between 100Ω and 1MΩ.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
A metal with temperature coefficient of resistance has a value 200, its initial resistance is given by 40Ω. For an increase in 300c to350c what will be the final resistance value?
40 KΩ
4 KΩ
40 Ω
400 Ω
Explanation:
Answer obtained using expression RT=R0(1+αΔT), where α represents temperature coefficient of resistance, R0 and RT represents initial and final resistance values.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
What will happen for resistivity metal and semiconductor if the temperature is increased?
Increases
Decreases
For metal increases and for semiconductor decreases
For metal decreases and for semiconductor increases
Explanation:
Metal has a positive temperature coefficient of resistance and semiconductor has a negative temperature coefficient of resistance.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Resistive transducers are ______________
Primary transducers
Secondary transducers
Either primary or secondary
None of the mentioned
Explanation:
Resistive transducers may be primary or secondary transducers according to application.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Which of the following can be measured using change in resistivity?
Temperature
Visible radiation
Moisture content
All of the mentioned
Explanation:
Change in resistivity can be brought in the measurement of all the mentioned quantities, as resistivity is sensitive to temperature.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Thermistors have high stability.
True
False
Explanation:
Stability of thermistors are not satisfactory. They can be improved by using high temperature.