Process Control and Instrumentation

131. Number of poles in a system with transfer function 1/(S² + 2S² + 1) is

1. 2
2. 5
3. 3
4. 1

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132. On-off control which is a special case of proportional control, has a band width of about _________ percent.

1. 100
2. 75
3. 25
4. 0

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133. On-off controllers are normally used for

1. Low loads
2. Temperature changes
3. Flow rate changes
4. None of these

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134. Operating range of a temperature measuring instrument is 800 to 1600°C. It could be a/an _________ pyrometer.

1. Radiation
2. Optical
3. Photoelectric
4. None of these

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135. Optical activity of a solution can be determined using a

1. Polarimeter
2. Polarograph
3. Dilatometer
4. Refractometer

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136. Ordinary mercury in glass thermometer is used for measuring temperature upto 120°C. However, for measuring higher temperature upto _________ °C, thermometer is made by filling nitrogen under pressure above the mercury, which stops the evaporation of mercury and reduces the chance of broken thread of mercury.

1. 250
2. 350
3. 550
4. 700

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137. Out of the following temperature measuring instruments, the measurement accuracy will be minimum for the

1. Mercury in glass thermometer
2. Optical pyrometer
3. Iron-constantan thermocouple
4. Alcohol filled thermometer

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138. Out of the following thermocouple wire insulating material, the highest temperature rating is for

1. Teflon
2. Ceramic fibre
3. Asbestos
4. Fibre glass

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139. Paramagnetism method is not used for the composition determination of _________ in gases.

1. Oxygen
2. Oxides of nitrogen
3. Carbon dioxide
4. Any of these

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140. pH meter has

1. One cell
2. Two cells
3. Three cells
4. No cell

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