Process Control and Instrumentation

211. The level of a liquid under pressure can be determined using

1. Bubbler system
2. Differential pressure manometer
3. Diaphragm box system
4. Air-trap system

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212. The maximum service temperature for fibre glass used as thermocouple wire insulation material is _________ °C.

1. 250
2. 500
3. 750
4. 1000

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213. The offset introduced by proportional controller with gain K_c in response of first order system can be reduced by

1. Reducing value of K_c
2. Introducing integral control
3. Introducing derivative control
4. None of the above

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214. The open loop transfer function of a control system is KR/(1 + TS). This represents

1. A first order system
2. Dead time system
3. A first order time lag
4. A second order system

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215. The open loop transfer function of a process is K [{(s + 1) (s + 4)}/{(s + 2) (s + 3)}]. In the root locus diagram, the poles will be at

1. -1, -4
2. 1, 4
3. -2, -3
4. 2, 3

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216. The operation of a Rotameter is based on

1. Variable flow area
2. Rotation of a turbine
3. Pressure drop across a nozzle
4. Pressure at a stagnation point

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217. The pressure sensing element of elastic type pressure gauge is never made in the form of a

1. Bellow
2. Diaphragm
3. Strip
4. Bourdon tube

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218. The response of two tanks of same size and resistance in series is

1. Under damped
2. Critically damped
3. Over damped
4. None of the above

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219. The root locus method, a pole of a transfer function G(s) is the value of s for which G(s) approaches

1. -1
2. 0
3. 1
4. ∞

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220. The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function K (s + 1)/[2 (2s + 1) (3s + 1)] will have a definite number of loci for variation of K from 0 to ∞. The number of loci is

1. 1
2. 2
3. 3
4. 4

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