Process Control and Instrumentation MCQs

Question 1

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

Accepted Answer

Volumetric expansion

Answer

Increase of pressure

Answer

Increase of thermal conductivity

Answer

Differential linear expansion

Question 2

Characteristic equation is the denominator of __________ loop transfer function.

Accepted Answer

Closed

Answer

Open

Answer

Both A & B

Answer

Neither A nor B

Question 3

Thermisters which have a very high temperature co-efficient of resistivity belong to the class of solid called

Accepted Answer

Semi conductors

Answer

Dielectrics

Answer

Insulators

Answer

Conductors

Question 4

A manometer measures the __________ pressure.

Accepted Answer

Gauge

Answer

Atmospheric

Answer

Absolute

Answer

None of these

Question 5

Pick out the wrong statement.

Accepted Answer

CO 2 is the strongest paramagnetic gas

Answer

O 2 , NO and NO 2 exhibit paramagnetic properties as a result of unpaired electrons

Answer

Paramagnetic susceptibility of gases decreases with temperature

Answer

Paramagnetic susceptibility of gases permits the measurement of their concentration

Question 6

Phase margin is equal to

Accepted Answer

180° - phase lag

Answer

Phase lag - 180°

Answer

Phase lag + 180°

Answer

Phase lag + 90°

Question 7

Zirconia probe is used for the measurement of

Accepted Answer

% O 2 in flue gas

Answer

Humidity of air

Answer

% CO 2 in flue gas

Answer

Speed of a submarine

Question 8

Emf developed by a thermocouple while measuring a temperature of 400°C is 22 mV. The type of thermocouple used is

Accepted Answer

Iron-constantan

Answer

Chromel-alumel

Answer

Platinum-rhodium

Answer

Platinum-platinum+rhyodium

Question 9

Magnetic flowmeters are generally not used for the velocity/flow measurement of hydrocarbons due to their

Accepted Answer

Low electrical conductivity

Answer

Low thermal conductivity

Answer

High viscosity index

Answer

Low flash point