Process Control and Instrumentation MCQs

Question 1

Thermal conductivity cell is the primary element of a/an __________ analyser.

Accepted Answer

Carbon dioxide

Answer

Oxygen

Answer

Carbon monoxide

Answer

Sulphur dioxide

Question 2

Bode diagram are generated from output response of the system subjected to which of the following input?

Accepted Answer

Sinusoidal

Answer

Impulse

Answer

Step

Answer

Ramp

Question 3

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

Accepted Answer

$$0,\,\frac{\pi }{2}$$

Answer

$$ - \infty ,\,\frac{\pi }{2}$$

Answer

$$ - \frac{\pi }{2},\,\frac{\pi }{2}$$

Answer

$$ - \frac{\pi }{2},\,0$$

Question 4

The transfer function for a P-D controller is

Accepted Answer

$${{	ext{K}}_{	ext{c}}}\left( {1 + {	au _{	ext{D}}}{	ext{s}}} ight)$$

Answer

$${{	ext{K}}_{	ext{c}}}\left( {1 + \frac{1}{{{	au _{	ext{D}}}{	ext{s}}}}} ight)$$

Answer

$${{	ext{K}}_{	ext{c}}}{	au _{	ext{D}}}{	ext{s}}$$

Answer

$$\frac{{{{	ext{K}}_{	ext{c}}}}}{{{	au _{	ext{D}}}{	ext{s}}}}$$

Question 5

An amplitude ratio of 0.1 corresponds to __________ decibels.

Accepted Answer

-20

Answer

20

Answer

10

Answer

-10

Question 6

Continuous flue gas analyser makes use of paramagnetic properties of some of its constituents, which move towards the strongest part of the magnetic field thus displacing diamagnetic gases. Which of the following gases is diamagnetic?

Accepted Answer

CO 2

Answer

O 2

Answer

NO

Answer

NO 2

Question 7

What is the Laplace transform of sin t?

Accepted Answer

$$\frac{1}{{{{	ext{s}}^2} + 1}}$$

Answer

$$\frac{{	ext{s}}}{{{{	ext{s}}^2} + 1}}$$

Answer

$$\frac{1}{{{{	ext{s}}^2} - 1}}$$

Answer

$$\frac{{	ext{s}}}{{{{	ext{s}}^2} - 1}}$$

Question 8

For an input forcing function, X(t) = 2t 2 , the Laplace transform of this function is

Accepted Answer

$$\frac{4}{{{{	ext{s}}^3}}}$$

Answer

$$\frac{2}{{{{	ext{s}}^2}}}$$

Answer

$$\frac{4}{{{{	ext{s}}^2}}}$$

Answer

$$\frac{2}{{{{	ext{s}}^3}}}$$

Question 9

Ordinary mercury in glass thermometer is used for measuring temperature upto 120°C. However, for measuring higher temperature upto __________ °C, thermometer is made by filling nitrogen under pressure above the mercury, which stops the evaporation of mercury and reduces the chance of broken thread of mercury.

Accepted Answer

550

Answer

250

Answer

350

Answer

700