Process Control and Instrumentation

71. Find the ultimate gain and frequency for a proportional controller in the case of a process having the transfer function G_p(s) = 1/(4s + 1)(2s + 1)(s + 1).

1. w = 1/√14, K_c = 45/7 √14
2. w = √(7/6), K_c = 46/3
3. w = 1, K_c = 13
4. w = √(7/8), K_c = 45/4

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72. Flame photometry is used for the determination of compositional analysis of

1. Solids
2. Alkali metals
3. Natural gas
4. Isotopes

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73. Flapper nozzle is used in a/an _________ controller.

1. Electronic
2. Hydraulic
3. Pneumatic
4. None of these

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74. Flow rate measurement of hostile acids and alkalis can be most suitably done by a/an

1. Venturimeter
2. Orificemeter
3. Magnetic flow meter
4. Hot wire anemometer

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75. Flow rate of a river is measured by a/an

1. Pitot tube
2. Vane meter
3. Kennison nozzle
4. Open weir

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76. Flow rate of sludge is not measured by a/an

1. Orificemeter
2. Open weir
3. Kennison nozzle
4. Both (B) & (C)

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77. Flow rate of those fluids which are insensitive to changes in their density, viscosity or flow velocity profile can be best measured by a

1. Magnetic flowmeter
2. Pitot tube
3. Flow nozzle type flowmeter
4. Turbine flowmeter

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78. Flow rate through an orifice is _________ the pressure differential.

1. Proportional to
2. Inversely proportional to the square root of
3. Proportional to the square root of
4. Inversely proportional to the square of

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79. For a feed back control system to be stable, the

1. Roots of the characteristic equation should be real
2. Poles of the closed loop transfer function should lie in the left half of the complex plane
3. Bode plots of the corresponding open loop transfer function should monotonically decrease
4. Poles of the closed loop transfer function should lie in the right half of the complex plane

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80. For an input forcing function, X(t) = 2t², the Laplace transform of this function is

1. 2/S²
2. 4/S²
3. 2/S³
4. 4/S³

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