Process Control Instrumentation Indicator MCQ Test - Set 15 - ObjectiveBooks

# Practice Test: Question Set - 15

1. Positioning controllers are used for
(B) Temperature changes
(D) Flow rate changes

2. Typical specifications for design stipulates the gain margin and phase margin to be respectively
(A) > 1.7 and > 30°
(B) < 1.7 and > 30°
(C) < 1.7 and < 30°
(D) > 1.7 and < 30°

3. Operating range of a temperature measuring instrument is 800 to 1600°C. It could be a/an _________ pyrometer.
(B) Optical
(C) Photoelectric
(D) None of these

4. For the block diagram shown below: The characteristic equation is
(A) τl S (τps + 1) + Kc . Kp (τlS + 1) ed s = 0
(B) (τmS + 1) (τpS + 1) + Km . Kp ed S = 0
(C) τl Sm S + 1) (τp S + 1) +Kc . Kp . Km (τl s + 1) edS = 0
(D) (τms + 1) (τp s + 1) + Kc . Kp . Km . edS = 0

5. Instrumentation in a plant offers the advantage of
(A) Greater safety of operation
(B) Better quality of product
(C) Greater operation economy
(D) All (a), (b) and (c)

6. A bimetallic thermometer as compared to industrial mercury in glass thermometer has almost the same
(A) Temperature measuring range (- 40°C to 450°C)
(B) Accuracy (± 1% of span)
(C) Speed of response
(D) All a, b & c

7. Magnetic flowmeters are generally not used for the velocity/flow measurement of hydrocarbons due to their
(A) Low thermal conductivity
(B) Low electrical conductivity
(C) High viscosity index
(D) Low flash point

8. The maximum service temperature for fibre glass used as thermocouple wire insulation material is ________ °C.
(A) 250
(B) 500
(C) 750
(D) 1000

9. Routh stability method uses _________ loop transfer function.
(A) Open
(B) Closed
(C) Either (a) or (b)
(D) Neither (a) nor (b)

10. The temperature range for which copper resistance thermometer can be used is ________ °C.
(A) 0 to 150
(B) -200 to 150
(C) 350 to 750
(D) 500 to 900

11. The function of a transducer is to
(A) Modify the input signal
(B) Amplify the input signal
(C) Convert the primary signal into a more useful quantity, usually an electric impulse
(D) Codify/decodify the input signal

12. Time constant is the
(A) Time taken by the controlled variable to reach 63.2% of its full change
(B) Same as transportation lag
(D) Time required by the measured variable to reach 63.2% of its ultimate change

13. _________ thermometer cannot measure sub-zero (< 0° C) temperature,
(A) Mercury in glass
(B) Bimetallic
(C) Vapor pressure
(D) Resistance

14. Continuous shell temperature measurement in a liquid-liquid heat exchanger is done by a
(A) Thermocouple
(B) Resistance thermometer
(C) Mercury in glass thermometer
(D) Vapor pressure thermometer

15. A mercury thermometer cannot be used to measure the temperature below the freezing point of mercury, which is ________ °C.
(A) -38.9
(B) -11.9
(C) -60.9
(D) -80.9

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