Process Control and Instrumentation

51. Concentration of sugar solution can be determined by the

1. Polarimetry
2. Flame photometry
3. Emission spectroscopy
4. Oscillometry

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52. Configuration of Bourdon spring tube is never made of _________ shape.

1. Circular
2. Semi-circular
3. Helical
4. Spiral

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53. Continuous flue gas analyser 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?

1. CO₂
2. O₂
3. NO
4. NO₂

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54. Continuous measurement of moisture content of paper in paper industry is done by measuring the

1. Thermal conductivity through the paper
2. Electrical resistance through the paper
3. Magnetic susceptibility
4. None of these

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55. Continuous measurement of moisture in paper is done by

1. Sling psychrometer
2. Hair-hygrometer
3. Weighing
4. High resistance Wheatstone bridge circuit

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56. Continuous measurement of specific gravity of a liquid is done by

1. Hydrometer
2. Contact-type electric indicators
3. Displacement meter
4. Both (A) and (C)

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57. Continuous shell temperature measurement in a liquid-liquid heat exchanger is done by a

1. Thermocouple
2. Resistance thermometer
3. Mercury in glass thermometer
4. Vapor pressure thermometer

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58. Conversion formula for converting amplitude ratio (AR) into decibels is

1. Decibel = 20 log10 (AR)
2. Decibel = 20 loge (AR)
3. Decibel = 20 log10 (AR)0.5
4. Decibel = 20 loge (AR)0.5

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59. Dead zone is the

1. Same as time constant
2. Same as transportation lag
3. Maximum change in the variable that does not change the reading of the instrument
4. None of these

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60. Degree to which an instrument indicates the changes in measured variable without dynamic error is called its

1. Speed of response
2. Reproducibility
3. Fidelity
4. Static characteristics

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