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process control section 1 Flashcards

1
Q

Which of the following is an undesirable
dynamic characteristic of an instrument?
a. Reproducibility
b. Dead zone
c. Time lag
d. Static error

A

c

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2
Q

Which of the following is not the triple point
of water?
a. 32°R
b. 273°K
c. 492°R
d. 32°F

A

a

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3
Q

Pick out the one which is a first order instrument.
a. Mercury in glass thermometer (without any
covering or air gap).
b. Bare metallic thermometer.
c. Bare vapor pressure thermometer.
d. All (a), (b) and (c).

A

d

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4
Q

Load cells are used for the measurement of
a. Stress
b. Weight
c. Strain
d. velocity

A

b

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5
Q

Which of the following is the dynamic
characteristics of an instrument?
a. Reproducibility
b. Sensitivity
c. Dead zone
d. Fidelity

A

d

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6
Q

Pick out the wrong statement.
a. O2, NO and NO2 exhibit paramagnetic
properties as a result of unpaired electrons.
b. CO2 is the strongest paramagnetic gas.
c. Paramagnetic susceptibility of gases
decreases with temperature.
d. Paramagnetic susceptibility of gases
permits the measurement of their
concentration.

A

b

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7
Q

The __________ of a vapor pressure
thermometer is a functioning element.
a. Pointer
b. bourdon tube
c. Bulb
d. none of these

A

a

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8
Q

A negative gain margin expressed in decibels
means a/an __________ system.
a. Stable
b. Unstable
c. critically damped
d. none of these

A

b

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8
Q

Flapper nozzle is used in a/an __________
controller.
a. Electronic
b. Hydraulic
c. Pneumatic
d. none of these

A

c

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8
Q

Thermistor, which has high temperature co-
efficient of resistivity, is used as the sensing

element in resistance thermometer. It is a/an
a. Insulator
b. Conductor
c. solid semi-conductor
d. liquid semi-conductor

A

c

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9
Q

Typical specifications for design stipulates the
gain margin and phase margin to be respectively
a. 1.7 and > 30°
b. < 1.7 and > 30°
c. < 1.7 and < 30°
d. 1.7 and < 30°

A

a

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10
Q

Working principle of radiation pyrometer is
based on the
a. Wien’s law
b. Kirchoffs law
c. Stafan-Boltzman law
d. Seebeck effect

A

c

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11
Q

Which of the following relates the emf.
generated in a single homogeneous wire to the
temperature difference?
a. Peltier effect
b. Thomson effect
c. Seebeck effect
d. none of these

A

b

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12
Q

Dilute wine was used as a thermometric liquid
initially to develop temperature scale. First
emperical temperature scale developed was the
__________ scale.
a. Kelvin
b. Centigrade
c. Fahrenheit
d. Reaumer

A

c

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13
Q

In a single tank system, the transfer function of
level to inlet flow rate is
a. R/TS
b. R/(TS + 1)
c. l(TS + l)
d. 1/TS

A

b

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14
Q

Which of the following is a desirable
characteristic of an instrument?
a. High drift
b. High fidelity
c. High measuring lag
d. Poor reproducibility

A

b

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15
Q

The operation of a rotameter is based on
a. variable flow area.
b. rotation of a turbine.
c. pressure drop across a nozzle.
d. pressure at a stagnation point.

A

a

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16
Q

The temperature of tempering oil baths
maintained at 400°C during heat treatment of steel
is measured by a/an __________ thermocouple.
a. Chromel-alumel
b. Iron-constantan
c. platinum-platinum/rhodium
d. none of these.

A

b

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17
Q

Instrumentation in a plant offers the advantage
of
a. greater safety of operation
b. better quality of product
c. greater operation economy
d. all (a), (b) and (c)

A

d

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18
Q

Which of the following temperature measuring
instruments need not touch the object whose
temperature is being measured?
a. Radiation/infrared pyrometer
b. Filled system thermometer
c. Mercury in glass thermometer
d. Thermo electric pyrometer

A

a

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19
Q

Thermal conductivity measurement com-prises
the working principle of a
a. CO2 analyser
b. Polarimeter
c. Spectrometer
d. chromatograph

A

a

20
Q

Response of a system to a sinusoidal input is
called __________ response.
a. Impluse
b. unit step
c. Frequency
d. none of these

A

c

21
Q

The closed loop pole of a stable second order
system could be
a. both real and positive.
b. complex conjugate with positive real parts.
c. both real and negative.

A

c

22
Q

Smoke density of the flue gas going out of the
chimney is measured by a
a. Polarograph
b. thermal conductivity meter
c. photo electric cell
d. chromatograph

A

c

23
Q

Transfer function of transportation lag is
a. e^(TS)
b. e^(-TS)
c. 1/(TS+1)
d. none of these

A

b

24
Q

Temperature measuring instruments are
standardised mostly with __________ points of
pure substances.
a. Melting
b. Boiling
c. both (a) & (b)
d. neither (a) nor (b)

A

c

25
Q

Pick out the first order system from among the
following.
a. Damped vibrator.
b. Mercury in glass thermometer kept in
boiling water.
c. Interacting system of two tanks in series.
d. Non-interacting system of two tanks in
series.

A

b

26
Q

The maximum service temperature for fibre
glass used as thermocouple wire insulation material
is __________ °C.
a. 250
b. 500
c. 750
d. 1000

A

c

27
Q

Which of the following controllers has the least
maximum deviation?
a. P-controller
b. P-I controller
c. P-I-D controller
d. P-D controller

A

d

28
Q

Volumetric expansion is the working principle
of the __________ thermometers.
a. mercury in glass
b. constant volume gas
c. vapor pressure
d. bimetallic

A

a

29
Q

Which of the following measurements can be
made by the measurement of emf?
a. pH value
b. Degree of hydrolysis
c. Composition of complex ions
d. All (a), (b) & (c)

A

d

30
Q

A magnetic flowmeter is
a. based on the principle of Faraday’s law.
b. capable of measuring the flow rate of
slurries and electrolytes.
c. based on the linear relationship between the
fluid flow rate and the induced voltage.
d. all (a), (b) and (c).

A

d

31
Q

Zirconia probe is used for the continuous
measurment of __________ flue gases going out of
the furnace.
a. oxygen in
b. carbon dioxide in
c. carbon monoxide in
d. temperature of

A

a

32
Q

Strain gage pressure transducers are used to
measure __________ pressures.
a. gage as well as vacuum
b. absolute as well as differential
c. both (a) and (b)
d. neither (a) nor (b)

A

c

33
Q

The transfer function for a PID controller is
(where, τ i is the integral (reset) time and τD is the
derivative time.)
a. Kc(1 + τis + τD ). s
b. Kc(1+1/(TiS)+TD.S)
c. Kc(1+Ti.S+1/(TDS))
d. Kc(1+1/(TiS)+1/TDS)

A

b

34
Q

Compositional analysis of __________ is done
using mass spectrometer.
a. an isotope
b. natural gas
c. a solid
d. an alloy

A

a

35
Q

The function of a transducer is to
a. modify the input signal.
b. amplify the input signal.
c. convert the primary signal into a more
useful quantity, usually an electric impulse.
d. codify/decodify the input signal.

A

c

36
Q

Nichol’s chart deals with
a. A.R.vs. phase lag of first order.
b. A.R. vs. phase lag of second order.
c. closed loop values vs. open loop values.
d. frequency response values of controllers.

A

c

37
Q

Which of the following thermocouples will give
the highest output for the same value of hot and cold
junction temperature?
a. Platinum-platinum + rhodium.
b. Iron-constantan.
c. Chromel-constantan.
d. All will give the same output.

A

c

38
Q

A proportional controller with a gain of Kc is
used to control a first order process. The offset will
increase, if
a. Kc is reduced.
b. Kc is increased.
c. integral control action is introduced.
d. derivative control action is introduced.

A

a

39
Q

The symbol for “capillary line” in
instrumentation diagram is
a.
b. line X line X line X line
c.
d.

A

b

40
Q

__________ is undesirable in thermocouples
used in industries,
a. Linear relation of emf to temperature
b. Corrosion resistance
c. Oxidation resistance
d. Non-linear relation of emf to temperature

A

d

40
Q

Select the correct statement from the following.
a. The frequency response of a pure capacity
process is unbounded.
b. The phase lag of a pure time delay system
decreases with increasing frequency.
c. The amplitude ratio of a pure capacity
process is inversely proportional to
frequency.
d. The amplitude ratio of a pure time delay
system increases with frequency.

A

c

40
Q

For an input forcing function, X(t) = 2t2, the
Laplace transform of this function is
a. 2/s2
b. 4/s2
c. 2/s3
d. 4/s3

A

d

41
Q

Continuous shell temperature measurement in a
liquid-liquid heat exchanger is done by a
a. Thermocouple
b. resistance thermometer
c. mercury in glass thermometer
d. vapor pressure thermometer

A

a

42
Q

The __________ of a vapor pressure
thermometer is a secondary element.
a. Pointer
b. Bourdon tube
c. Bulb
d. none of these

A

b

43
Q

Emf developed by a thermocouple, while
measuring a temperature of 600°C is about 5.5 mV.
The type of thermocouple used is
a. Chromel-alumel
b. Iron-constantan
c. platinum-platinum+rhodium
d. either (a), (b) or (c)

A

c

44
Q

Which of the following relates the absorption &
evolution of heat at the junctions of a thermocouple
to the current flow in the circuit?
a. Seebeck effect
b. Peltier effect
c. Joule heating effect
d. Thomson effect

A

b

45
Q

The second order system with the transfer
function 4
SS2+2SS+4 has a damping ratio of
a. 2.0
b. 0.5
c. 1.0
d. 4.0

A

b

46
Q

In a shell and tube heat exchanger, the flow rate
of heating/cooling fluid is the __________ variable.
a. Load
b. Controlled
c. Manipulated
d. none of these

A

c

47
Q
A

process ctrl inst (7 decks)

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