Process Control and Instrumentation

311. Working principle of bimetallic thermometers is difference in linear co-efficient of thermal expansion of two strips of different metals welded together. Which of the following has the maximum thermal co-efficient of linear expansion?

1. Nickel
2. Brass
3. Chromel
4. Invar

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312. Working principle of disappearing filament type optical pyrometer is based on the

1. Wien's law
2. Seebeck effect
3. Kirchoff's law
4. Peltier effect

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313. Working principle of mercury in glass thermometer is

1. Volumetric expansion
2. Pressure rise with temperature
3. Linear expansion
4. None of these

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314. Working principle of mercury in glass thermometer is based on the _________ of mercury with increase in temperature.

1. Increase of pressure
2. Increase of thermal conductivity
3. Volumetric expansion
4. Differential linear expansion

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315. Working principle of mercury in glass thermometer is based on volumetric expansion of mercury with increase in temperature. Which of the following undergoes minimum volumetric expansion for a given temperature change?

1. Water
2. Mercury
3. Methyl alcohol
4. Carbon-tetrachloride

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316. Working principle of radiation pyrometer is based on the

1. Wien's law
2. Kirchoff’s law
3. Stefan Boltzmann law
4. Seebeck effect

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317. Zirconia probe is used for the continuous measurement of _________ flue gases going out of the furnace.

1. Oxygen in
2. Carbon dioxide in
3. Carbon monoxide in
4. Temperature of

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