Practice Test: Question Set - 15
1. Positioning controllers are used for
- (A) Low loads
- (B) Temperature changes
- (C) High loads
- (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.
- (A) Radiation
- (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) e-τd s = 0
- (B) (τmS + 1) (τpS + 1)
+ Km . Kp e-τd S =
0
- (C) τl S(τm S + 1) (τp S +
1) +Kc . Kp . Km (τl s +
1) e-τdS = 0
- (D) (τms + 1) (τp s +
1) + Kc . Kp . Km .
e-τdS = 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
- (C) Same as dead time
- (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