Process Control and Instrumentation MCQs

Question 1

__________ is the static characteristics of an instrument,

Accepted Answer

Drift

Answer

Response

Answer

Tine lag

Answer

Dynamic error

Question 2

Temperature of __________ can not be measured by an optical or radiation pyrometer.

Accepted Answer

Hot blast (air) from stoves

Answer

Molten slag flowing out of blast furnace

Answer

Combustion space in boilers

Answer

Rotary limestone calcination kiln

Question 3

Find the ultimate gain and frequency for a proportional controller in the case of a process having the transfer function $${{	ext{G}}_{	ext{p}}}\left( {	ext{s}} ight) = \frac{1}{{\left( {4{	ext{s}} + 1} ight)\left( {2{	ext{s}} + 1} ight)\left( {{	ext{s}} + 1} ight)}}.$$

Accepted Answer

$${	ext{w}} = \sqrt {\frac{7}{6}} ,\,{{	ext{K}}_{	ext{c}}} = \frac{{46}}{3}$$

Answer

$${	ext{w}} = \frac{1}{{\sqrt {14} }},\,{{	ext{K}}_{	ext{c}}} = \frac{{45}}{{7\sqrt {14} }}$$

Answer

$${	ext{w}} = 1,\,{{	ext{K}}_{	ext{c}}} = 13$$

Answer

$${	ext{w}} = \sqrt {\frac{7}{8}} ,\,{{	ext{K}}_{	ext{c}}} = \frac{{45}}{4}$$

Question 4

Composition of alloys can be determined by

Accepted Answer

Polarograph

Answer

Chromatograph

Answer

Refractrometer

Answer

None of these

Question 5

Vapour actuated pressure spring thermometer does not require ambient temperature compensation. Ambient temperature compensation is provided in gas or liquid expansion pressure spring thermometer by

Accepted Answer

All of the above

Answer

Making the volume of thermometer bulb as large as conveniently possible

Answer

Reducing the volume of the capillary to a minimum

Answer

Reducing the volume of the receiving element to a minimum

Question 6

What is the normal percentage of rhodium in platinum + rhodium element used in the thermocouple?

Accepted Answer

13

Answer

0.1

Answer

3

Answer

29

Question 7

What is the Laplace transform of impulse input having magnitude 'X'?

Accepted Answer

1

Answer

X

Answer

X 2

Answer

$$\frac{{	ext{1}}}{{	ext{X}}}$$

Question 8

Emf developed by a thermocouple, while measuring a temperature of 600°C is about 5.5 mV. The type of thermocouple used is

Accepted Answer

Platinum-platinum+rhodium

Answer

Chromel-alumel

Answer

Iron-constantan

Answer

Either A, B or C

Question 9

A simple pitot tube measures the

Accepted Answer

Static pressure

Answer

Average velocity

Answer

Maximum velocity

Answer

Point velocity