Process Control and Instrumentation MCQs

Question 1

The offset introduced by proportional controller with gain K c in response of first order system can be reduced by

Accepted Answer

Introducing integral control

Answer

Reducing value of K c

Answer

Introducing derivative control

Answer

None of the above

Question 2

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

Accepted Answer

Peltier

Answer

Thomson

Answer

Seebeck

Answer

None of these

Question 3

In a shell and tube heat exchanger, the flow rate of heating/cooling fluid is the __________ variable.

Accepted Answer

Manipulated

Answer

Load

Answer

Controlled

Answer

None of these

Question 4

Platinum resistance thermometer is the international standard for temperature measurement between

Accepted Answer

Both A and B

Answer

Triple point of hydrogen and freezing point of antimony

Answer

13.81°K to 903.9°K

Answer

Neither A nor B

Question 5

Mercury thermometer can be used to measure the temperature upto __________ °C.

Accepted Answer

350

Answer

100

Answer

250

Answer

750

Question 6

Cascade control means

Accepted Answer

More than one feed-back loop

Answer

Feed forward control

Answer

On-off control

Answer

One feed-back loop

Question 7

Resistance of a gas in a vessel is given by (where, P = pressure, V = volume of the vessel, n = number of moles of the gas, R = gas constant)

Accepted Answer

$$\frac{{	ext{V}}}{{{	ext{nRT}}}}$$

Answer

$$\frac{{{	ext{nRT}}}}{{	ext{V}}}$$

Answer

$$\frac{{{	ext{nRT}}}}{{	ext{P}}}$$

Answer

$$\frac{{	ext{P}}}{{{	ext{nRT}}}}$$

Question 8

Dome temperature of blast furnace stove is most accurately measured by a

Accepted Answer

Platinum-platinum/rhodium ther-mocuple

Answer

Radiation pyrometer

Answer

Iron-constantan thermocouple

Answer

Platinum resistance thermometer

Question 9

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

Accepted Answer

Photoelectric

Answer

Radiation

Answer

Optical

Answer

None of these