Process Control & Instrumentation Objective Questions – Set 2

In a closed loop system, the process to be controlled is an integrating process with transfer function l/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit

Time constant is the

Which thermocouple can be used to measure a temperature of around 1400°C ?

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

Pick out the most suitable instrument for measuring temperature in the range of-40 to 425°C.

Which of the following thermocouples can measure the maximum temperature ?

Specific gravity of a liquid can not be measured by a/an

Flow rate of those fluids which are insensitive to changes in their density, viscosity or flow velocity profile can be best measured by a

Humidity of air can be determined by a

Radiation pyrometers as compared to thermocouples

The fluid used in hydraulic controller is

A non-linear chemical system is exemplified by a/an

Liquid flow rate in a small channel is best measured by a/an

Thermocouple in a thermal well behaves as a true

Which of the following thermocouple materials does not contain nickel ?

According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is

The initial value (t=0) of the unit step response of the transfer function [(s + 1)/(2s + 1)] is

__________ temperature scale assigns 0° to the 'ice point' and 80° to the 'steam point'.

Which of the following fluid flow measuring devices can measure the largest flow rate ?

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?

Dead zone is the

Gas chromatography is used for the measurement of

Thermal wells used in temperature measurements should have

Which of the following thermometers is not suitable for distant reading upto 60 metres?

Process degree of freedom indicates __________ number of controllers to be used.

__________ is the static characteristics of an instrument,

The time constant of a first order process with resistance R and capacitance C is

Configuration of Bourdon spring tube is never made of __________ shape.

A barometer measures the __________ pressure.

Accurate temperature measurement performance of a radiation pyrometer can not be affected, if the

Bode diagram is a plot of

Which of the following filled system expansion thermometer has the capability to measure the lowest temperature ?

Nitrogen gas constant volume thermometer is suitable for measuring a temperature of __________ °C.

A sinusoidal variation in the input passing through a linear first order system

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

Measurement of pressure in ammonia reactor is done by

Which of the following can not measure a temperature of 1600°C ?

Thermistors are made of

Flow rate of a river is measured by a/an

Thermodynamic celcius scale of temperature measurement is

Relationship between absorption/evolution of heat at the thermocouple junctions and the current flow in the circuit is given by __________ effect.

"A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency." This is __________ criterion.

Pick out the wrong statement

Strain gage uses an electrical conductor wire, which when elastically stretched increases in length and reduces in diameter. Both these dimensional changes result in __________ in the electrical resistance of the wire.

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

The __________ of a vapor pressure thermometer is a primary element.

The frequency response of a first order system, has a phase shift with lower and upper bounds given by

Range of hydrogen gas constant volume themometer is __________ °C.

Concentration of sugar solution can be determined by the