Match List I with List II Choose the correct answer from the options given below:LIST I LIST II A. Stroboscope I. Changes its electrical resistance with temperature B. Bolometer II. Generate thermoelectric emf C. Thermocouple III. Changes pressure to displacement D. Diaphragm IV. For measurement of rotary motion
A-IV, B-I, C-II, D-III
Match each device to the physical principle it uses.
A → IV, stroboscope: measurement of rotary motion. A stroboscope flashes a lamp at an accurately known, adjustable rate. When the flashing frequency matches the rotational speed of a shaft (or a submultiple of it), the marked rotor appears frozen, and the speed is read from the flash-rate dial. It is a non-contact tachometer, so it loads the machine not at all — the reason it is used on high-speed and delicate rotating equipment. (Care is needed with sub-harmonics, which also freeze the image.)
B → I, bolometer: changes its electrical resistance with temperature. Incident radiation (microwave or infrared) is absorbed by a tiny element — a thermistor bead or a thin metal film — whose temperature therefore rises, changing its resistance. The resistance change is read out in a bridge and is proportional to the absorbed power, which is why bolometers are the standard for microwave power measurement and for infrared imaging.
C → II, thermocouple: generates a thermoelectric emf. Two dissimilar metals joined at a hot junction develop a voltage by the Seebeck effect, roughly proportional to the temperature difference between the measuring and reference junctions:
\(E = \alpha\,(T_{hot}-T_{cold})\)
Because it produces its own output, the thermocouple is an active (self-generating) transducer — no excitation supply needed — but it does need cold-junction compensation.
D → III, diaphragm: changes pressure into displacement. A thin elastic disc clamped at its rim deflects at the centre in proportion to the pressure difference across it. That mechanical displacement is then converted to an electrical signal by a secondary transducer — a strain gauge bonded to the diaphragm, an LVDT core, or a capacitive pick-off. Diaphragms, bellows and Bourdon tubes are all pressure-to-displacement elements of this kind.
Note the pattern: B and C are both temperature-related but differ fundamentally — the bolometer is passive (resistance change, needs excitation) while the thermocouple is active (generates emf). That distinction is what the question is really testing.
Hence, the correct matching is A-IV, B-I, C-II, D-III.
Similar Questions
Which of the following statements are correct ?
A. Hygrometer measures the value of humidity directly
B. Hygrometer measures the value of humidity indirectly
C. Wien's bridge is used to measure the frequency of the signal
D. Wien's bridge is used to measure the amplitude of the signal
E. Bimetallic strip is a thermal expansion detector.
Choose the most appropriate answer from the options given below :
Which of the following statements are correct
A. Megnetostrictive transducer operation depends on the change of permeability of magnetic material is when strained.
B. Potentiometer is an active transducer.
C. Turbine flow meters are volumetric flow meters
D. Any metal can be thermistor.
E. Thermocouples are used in high accuracy measurements.
Choose the most appropriate answer from the options given below :
Match the following lists :
List – I List – II a. Electromechanical Device i. Seismic Device b. Optical Device ii. Piezo-electric c. Gyroscopic device iii. Interferometers d. Absolute motion device iv. Aerospace vehicle Choose the correct answer from the codes given below:
Consider the following transducers or transducer systems :
(a) Float elements
(b) Seismic system
(c) Gyroscope
Arrange the above transducers/systems in decreasing order of the availability of possible number of output signals.
Consider the following statements associated with electrical and electronic transducers
A. Little power is consumed by transducer
B. Mass intertia effects are not minimized
C. The response time is small
D. Transmission and processing the signal for the purpose of measurement are easier.
Choose the correct answer from the options given below:
Match List I with List II
LIST I LIST II A. Relative error I. The ability of tde device to give identical O/P when repeated measurements are made witd tde same I/P signal B. Precision II. The ratio of difference between measured value and tde true value to tde true value of tde measurand C. Caliberation III. The smallest increment in measure tdat can be detected witd certainity by tde instrument D. Resolution IV. The process of making adjustments or tde scale so tdat tde instrument reading conform to an accepted standard. Choose the correct answer from the options given below:
The fundamental law that is used in temperature measurement is known as
Assertion (A) : Normally, some standard signal conditioner and display devices are used with a transducer, unless they are custom-built to suit the requirements of the transducers.
Reason (R) : A transducer is a device which receives energy in one form and transfer it to a convenient form.
Select your answer using the codes given below :
Which of the following transducers are not linear ?
i. thermistor
ii. thermocouple
iii. IC sensorWhich of the following sensors has excellent linearity ?
Important Questions from Basics of Transducers
Which of the following can act as an inverse transducer?
For transducers, following statements are given:
(A) An optical interferometer is useful for measuring extremely small motions
(B) The damping ratio of a seismic instrument should be low for good dynamic performance
(C) A rate gyro is a relative motion measuring device
(D) A pneumatic motion transducer is non-linear over a wide range of motion
(E) A piezoelectric accelerometer can only be used for static motion measurement
Choose the correct answer from the options given below:
Choose the INCORRECT statement with respect to the use of electrical transducers.
Consider the following transducers:
1. LVDT
2. Piezoelectric
3. Thermocouple
4. Photovoltaic cell
5. Strain gauge
Which of these are active transducers?
Under which condition, Transducers must operate?
