Process Control and Instrumentation

31. A system with transfer function [(2S/4S) + 1] is of _________ order.

1. Zero
2. 1st
3. 2nd
4. 3rd

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32. A typical example of a physical system with under damped characteristic is a

1. U-tube manometer
2. Spring loaded diaphragm valve
3. CSTR with first order reaction
4. Thermocouple kept immersed in a liquid filled thermowell

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33. According to Bode stability criterion, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is

1. 0°
2. 45°
3. 90°
4. 180°

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34. Accurate temperature measurement performance of a radiation pyrometer cannot be affected, if the

1. Enhancement or attenuation of radiation occurs in the sighting path
2. Object and surrounding are at almost the same temperature
3. Object has varying emissivity
4. Object is transparent

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35. All the thermocouples used for temperature measurement use dissimilar metal

1. Strips
2. Bars
3. Wires
4. Beads

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36. An amplitude ratio of 0.1 corresponds to _________ decibels.

1. 20
2. -20
3. 10
4. -10

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37. An aneroid barometer measures the _________ pressure.

1. Atmospheric
2. Absolute
3. Vacuum
4. Gage

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38. An ideal PID controller has the transfer function [1 + (1/0.55) + 0.25]. The frequency at which the magnitude ratio of the controller is 1, is

1. 0.5/0.2
2. 0.2/0.5
3. 0.2 × 0.5
4. 1/√(0.2 × 0.5)

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39. Bimetal strips are not used in

1. Bimetallic thermometers
2. Thermocouples
3. Thermostats
4. Relays for opening & closing of electrical circuits

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40. Bode diagram are generated from output response of the system subjected to which of the following input?

1. Impulse
2. Step
3. Ramp
4. Sinusoidal

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