Process Control and Instrumentation MCQs

Question 1

Select the correct statement from the following.

Accepted Answer

The amplitude ratio of a pure capacity process is inversely proportional to frequency

Answer

The frequency response of a pure capacity process is unbounded

Answer

The phase lag of a pure time delay system decreases with increasing frequency

Answer

The amplitude ratio of a pure time delay system increases with frequency

Question 2

The temperature of tempering oil baths maintained at 400°C during heat treatment of steel is measured by a/an __________ thermocouple.

Accepted Answer

Iron-constantan

Answer

Chromel-alumel

Answer

Platinum-platinum/rhodium

Answer

None of these

Question 3

A mercury thermometer can not be used to measure the temperature below the freezing point of mercury, which is __________ °C.

Accepted Answer

-38.9

Answer

-11.9

Answer

-60.9

Answer

-80.9

Question 4

The thermal emf-temperature relationship of most thermocouples is

Accepted Answer

Parabolic

Answer

Linear

Answer

Exponential

Answer

Square root

Question 5

Which of the following thermocouple materials does not contain nickel?

Accepted Answer

None of these

Answer

Alumel

Answer

Chromel

Answer

Constantan

Question 6

Temperature measurement range of iron-constantan thermocouple is 0 to 870°C. It can be used to measure sub zero temperature, because at lower temperature

Accepted Answer

Both B and C

Answer

Emf produced is very low of the order of microvolt

Answer

Embrittlement of iron occurs

Answer

Rusting of iron takes place

Question 7

A bolometer is

Accepted Answer

Both A & B

Answer

Used for the measurement of thermal radiation

Answer

An element which senses optical input and delivers thermal output

Answer

Neither A nor B

Question 8

Working principle of mercury in glass thermometer is

Accepted Answer

Volumetric expansion

Answer

Pressure rise with temperature

Answer

Linear expansion

Answer

None of these

Question 9

The initial value (t = 0) of the unit step response of the transfer function $$\frac{{\left( {{	ext{s}} + 1} ight)}}{{\left( {2{	ext{s}} + 1} ight)}}$$ is

Accepted Answer

$$\frac{1}{2}$$

Answer

0

Answer

1

Answer

2