Transduction of Physical Variables Mid - I, September - 2014

1.Which of the following Liquid-in-glass thermometers can give the best temperature lower limit?
  • Mercury
  • Alcohol
  • Pentane
  • Mixture of propane and propylene
Answer: D
2.The thermoelectric emf is actually an effect distributed along the length of each single metal wire when _________
  • Voltage source is connected to it
  • Current source is connected to it
  • Both voltage and current sources are connected to it
  • Even when no source is connected to it
Answer: D
3.The output voltage of typical thermocouple is
  • Less than 1 milli volt
  • Less than 100 milli volt
  • Less than 1 volt
  • Less than 100 volts
Answer: B
4.Thermocouple which is not used in high-temperature processes in jet and rocket engines and nuclear reactor is
  • Copper/Constantan
  • Rhodium-Iridium/Rhodium
  • Tungsten/Rhenium
  • Boron/Graphite
Answer: A
5.If a 3rd metal C is introduced into the circuit. Then the 2 junctions so formed are at the same temperature. So the net emf is same as if the metal is absent this is known as
  • Peltier emf
  • Law of intermediate temperatures
  • Law of homogeneous circuits
  • Law of intermediate metals
Answer: B
6.The smallest measurement a transducer can detect is called as ____ of the instrument.
  • Precision
  • Resolution
  • Sensitivity
  • Error
Answer: B
7.Which of the following static characteristic is undesirable
  • Accuracy
  • Dead Zone
  • Reproducibility
  • Sensitivity
Answer: B
8.A first order system with a transfer function 1/(1 + s) is excited by a signal 10sin t. Its steady state output will be
  • 10 sin (2t - 45°)
  • 10 sin (t - 45°)
  • 7.07 sin (t + 45°)
  • 7.07sin(t - 45°)
Answer: D
9.Which of the following manometers shows greater sensitivity
  • U tube manometer
  • Well type manometer
  • Inclined tube manometer
  • All of the above show equal sensitivity
Answer: C
10.A pressure thermometer will not consist of
  • Sensitive bulb
  • Pressure – measuring device
  • Interconnecting capillary tube
  • Conductive sensors
Answer: D
11.The thermometer is initially at a temperature of 70°C and is suddenly placed in a liquid which is at 170°C. The thermometer indicates 133.2°C after a time interval of 3 Sec. The time constant of the thermometer is ________________ sec.
Answer: 3 sec
12.Barometer is used for the measurement of __________________ pressure.
Answer: Absolute
13.The mathematical expression for the relationship between the resistance of a thermistor and the absolute temperature of thermistor is _________________.
Answer:
14.A Pyroelectric detector converts the changes in incoming infrared radiation into _______________.
Answer: electrical signal
15.Dynamic characteristics are obtained by writing ______________ of the system.
Answer: differential equation
16.The output from thermocouple is in ______________ units.
Answer: mV
17._________________ is the sensor output that exists when it should be zero.
Answer: offset
18.Bimetallic strips are ___________________ type of sensors.
Answer: Thermal expansion type
19._______________ is the measure (degree) of reproducibility of the measurements.
Answer: Precision
20.A ___________________ converts a physical parameter to an electrical output.
Answer: Transducer