Process Control and Instrumentation Book MCQ Questions - Set 02 - ObjectiveBooks

# Practice Test: Question Set - 02

1. Pick out the symbol for "locally mounted instrument" in instrumentation diagram.

2. Working principle of mercury in glass thermometer is based on the __________ of mercury with increase in temperature.
(A) Increase of pressure
(B) Increase of thermal conductivity
(C) Volumetric expansion
(D) Differential linear expansion

3. Phase margin is equal to
(A) 180° - phase lag
(B) Phase lag - 180°
(C) Phase lag + 180°
(D) Phase lag + 90°

4. Continuous flue gas analyzer makes use of paramagnetic properties of some of its constituents, which move towards the strongest part of the magnetic field thus displacing diamagnetic gases. Which of the following gases is diamagnetic?
(A) CO2
(B) O2
(C) NO
(D) NO2

5. Change of angle of refraction with composition comprises the working principle of a
(A) Polarimeter
(B) Polarograph
(C) Spectrometer
(D) Refractometer

6. A non-linear chemical system is exemplified by a/an
(A) Isothermal CSTR
(B) Mixer
(C) Non-isothermal CSTR
(D) None of these

7. Mcleod gauge is used to measure the
(A) Point velocity
(B) Flow rate
(C) Vacuum
(D) Pressure

8. All the thermocouples used for temperature measurement use dissimilar metal
(A) Strips
(B) Bars
(C) Wires

9. Find the Laplace transform of the following input function shown in figure.
(A) (1 - e-s)/[S (1 - e-2s)]
(B) 2(1 - e-s)/S
(C) (1 - e-s)/[S (1 + e-s)]
(D) e-s (1 - e-s)/[S (1 + e-2s)]

(A) Same as time constant
(B) Same as transportation lag
(C) Maximum change in the variable that does not change the reading of the instrument
(D) None of these

11. A non-linear system will have _________ steady state values.
(A) One
(B) More than one
(C) Two
(D) Three

12. The time constant of a unity gain, first order plus time delay process is 5 min. If the phase lag at a frequency of 0.2 rad/min is 60°, then the dead time (in minutes) is
(A) 5π/12
(B) π/6
(C) π/12
(D) π/3

13. On-off control which is a special case of proportional control, has a band width of about _________ percent.
(A) 100
(B) 75
(C) 25
(D) 0

14. The transfer function for a P-D controller is
(A) Kc(1+τD s)
(B) Kc(1 +1/τD s)
(C) Kc τD s
(D) KcD s

15. In a feed-back control system G and H denote open loop and close loop transfer functions respectively. The output-input relationship is
(A) G/(1 + H)
(B) H/(1 + G)
(C) G/H
(D) H/G

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