Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ChELE Concept > Process Control and Instrumentation > Flashcards

Process Control and Instrumentation Flashcards

1
Q

Pick out the one which is a first order instrument.

A

All (a), (b) and (c)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Load cells are used for the measurement of

A

Weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which of the following is the dynamic characteristics of an instrument ?

A

Fidelity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Pick out the wrong statement.

A

CO2 is the strongest paramagnetic gas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The __________ of a vapor pressure thermometer is a functioning element.

A

Pointer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

A negative gain margin expressed in decibels means a/an __________ system.

A

Unstable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thermistor, which has high temperature co-efficient of resistivity, is used as the sensing element in resistance thermometer. It is a/an

A

solid semi-conductor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Flapper nozzle is used in a/an __________ controller.

A

pneumatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Typical specifications for design stipulates the gain margin and phase margin to be respectively

A

> 1.7 and > 30°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Working principle of radiation pyrometer is based on the

A

Stafan-Boltzman law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which of the following relates the emf. generated in a single homogeneous wire to the temperature difference ?

A

Thomson effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Dilute wine was used as a thermometric liquid initially to develop temperature scale. First emperical temperature scale developed was the __________ scale.

A

Fahrenheit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In a single tank system, the transfer function of level to inlet flow rate is

A

R/(TS + 1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which of the following is a desirable characteristic of an instrument ?

A

High fidelity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The operation of a rotameter is based on

A

variable flow area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

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

A

iron-constantan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Instrumentation in a plant offers the advantage of

A

all (a), (b) and (c)
(greater safety of operation
better quality of product
greater operation economy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which of the following temperature measuring instruments need not touch the object whose temperature is being measured ?

A

Radiation/infrared pyrometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Thermal conductivity measurement com-prises the working principle of a _________.

A

CO2 analyser

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Response of a system to a sinusoidal input is called __________ response.

A

frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The closed loop pole of a stable second order system could be

A

both real and negative.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Smoke density of the flue gas going out of the chimney is measured by a

A

photo electric cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Transfer function of transportation lag is

A

e-TS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Temperature measuring instruments are standardised mostly with __________ points of pure substances.

A

both (a) & (b)
(melting
boiling)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Pick out the first order system from among the following.

A

Mercury in glass thermometer kept in boiling water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

The maximum service temperature for fibre glass used as thermocouple wire insulation material is __________ °C.

A

500 °C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which of the following controllers has the least maximum deviation ?

A

P-D controller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Volumetric expansion is the working principle of the __________ thermometers.

A

mercury in glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

A magnetic flowmeter is

A

all (a), (b) and (c)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Zirconia probe is used for the continuous measurment of __________ flue gases going out of the furnace.

A

oxygen in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Strain gage pressure transducers are used to measure __________ pressures.

A

both (a) and (b)
(gage as well as vacuum
absolute as well as differential)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
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 + 1/τis + τD. s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Compositional analysis of __________ is done using mass spectrometer.

A

an isotope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

The function of a transducer is to

A

convert the primary signal into a more useful quantity, usually an electric impulse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Nichol’s chart deals with

A

closed loop values vs. open loop values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Which of the following thermocouples will give the highest output for the same value of hot and cold junction temperature ?

A

Chromel-constantan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

The symbol for “capillary line” in instrumentation diagram is

A

————-——

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

__________ is undesirable in thermocouples used in industries,

A

Non-linear relation of emf to temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Select the correct statement from the following.

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Continuous shell temperature measurement in a liquid-liquid heat exchanger is done by a

A

thermocouple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

The __________ of a vapor pressure thermometer is a secondary element.

A

Bourdon tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

platinum-platinum+rhodium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

Peltier effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

The second order system with the transfer function has a damping ratio of

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

In a shell and tube heat exchanger, the flow rate of heating/cooling fluid is the __________ variable.

A

manipulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

The second order system with the transfer function has a damping ratio of

A

0.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

A non-linear chemical system is exemplified by a/an

A

non-isothermal CSTR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

The transfer function for an ideal proportional plus reset controller (reset time T) is

A

Kc(1 + 1/TS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

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

A

0, π/2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Gas chromatography is used for the measurement of

A

concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Which of the following thermocouples can measure the maximum temperature ?

A

Tungsten-molybdenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Radiation pyrometers as compared to thermocouples

A

can measure higher temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Liquid flow rate in a small channel is best measured by a/an

A

pitot tube

55
Q

Specific gravity of a liquid can not be measured by a/an

A

anemometer

56
Q

__________ temperature scale assigns 0° to the ‘ice point’ and 80° to the ‘steam point’.

A

Reumur

57
Q

Dead zone is the

A

maximum change in the variable that does not change the reading of the instrument.

58
Q

Which of the following thermometers is not suitable for distant reading upto 60 metres?

A

Mercury in glass thermometer

59
Q

Degree to which an instrument indicates the changes in measured variable without dynamic error is called its

A

fidelity

60
Q

Thermistors are made of

A

metal oxides

61
Q

A barometer measures the __________ pressure.

A

absolute

62
Q

Humidity of air can be determined by a

A

sling psychrometer

63
Q

Thermocouple in a thermal well behaves as a true

A

multiple first order system

64
Q

The transfer function for a P-D controller is

A

Kc(1+τD s)

65
Q

Bode diagram is a plot of

A

log (AR) vs. log (f) and (Φ) vs. log (f)

66
Q

Working principle of disappearing filament type optical pyrometer is based on the

A

Wien’s law

67
Q

Strain gage uses an electrical conductor wire, which when elastically stretched increases in length and reduces in diameter. Both these dimensional changes result in __________ in the electrical resistance of the wire.

A

increase

68
Q

Pick out the wrong statement

A

CSTR can be considered as a distributed parameter system

69
Q

Range of hydrogen gas constant volume themometer is __________ °C.

A

0 to 100

70
Q

The __________ of a vapor pressure thermometer is a primary element.

A

bulb

71
Q

The time constant of a first order process with resistance R and capacitance C is

A

RC

72
Q

A sinusoidal variation in the input passing through a linear first order system

A

gets attenuated (magnitude decreases)

73
Q

Nitrogen gas constant volume thermometer is suitable for measuring a temperature of __________ °C.

A

> 100

74
Q

Pick out the most suitable instrument for measuring temperature in the range of-40 to 425°C.

A

bimetallic thermometer

75
Q

Accurate temperature measurement performance of a radiation pyrometer can not be affected, if the

A

object and surrounding are at almost the same temperature.

76
Q

Relationship between absorption/evolution of heat at the thermocouple junctions and the current flow in the circuit is given by __________ effect.

A

Peltier

77
Q

Configuration of Bourdon spring tube is never made of __________ shape.

A

circular

78
Q

Thermodynamic celcius scale of temperature measurement is

A

both (b) and (c)
(defined on the basis of melting point of ice and condensation temperature of water vapor.
having an interval of 100° between ice point to steam point.)

79
Q

According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is

A

180°

80
Q

In a closed loop system, the process to be controlled is an integrating process with transfer function l/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit

A

underdamped response

81
Q

Resistance of a gas in a vessel is given by (where, P = pressure, V = volume of the vessel, n = no. of moles of the gas, R = gas constant)

A

V/nRT

82
Q

Measurement of pressure in ammonia reactor is done by

A

Bourdon gauge

83
Q

The fluid used in hydraulic controller is

A

oil

84
Q

Flow rate of a river is measured by a/an

A

vane meter

85
Q

Which of the following thermocouple materials does not contain nickel ?

A

None of these.

86
Q

Flow rate of those fluids which are insensitive to changes in their density, viscosity or flow velocity profile can be best measured by a

A

magnetic flowmeter

87
Q

“A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency.” This is __________ criterion.

A

Bode stability

88
Q

Feed forward controller accounts for the __________ changes.

A

load

89
Q

Which thermocouple can be used to measure a temperature of around 1400°C ?

A

Platinum-platinum+rhodium

90
Q

Which of the following filled system expansion thermometer has the capability to measure the lowest temperature ?

A

Alcohol in glass thermometer

91
Q

Concentration of sugar solution can be determined by the

A

polarimetry

92
Q

In a single tank system, the transfer function of __________ to inlet flow rate is 1/TS+1.

A

outlet flow rate

93
Q

Which of the following can not measure a temperature of 1600°C ?

A

Platinum resistance thermometer

94
Q

The temperature range for which copper resistance thermometer can be used is __________ °C

A

-200 to 150

95
Q

Paramagnetism method is not used for the composition determination of __________ in gases.

A

carbon dioxide

96
Q

An amplitude ratio of 0.1 corresponds to __________ decibels.
20

A

-20

97
Q

For increased speed of response of an expansion pressure spring thermometer, the thermometer bulb should have a

A

all’a’, ‘b’ & ‘c’
(large area but small mass.
high thermal conductivity.
small specific heat.)

98
Q

Pressure of 0.0001 absolute psi can be measured by __________ gauge.

A

Mcloid

99
Q

Pirani gauge is used for the measurement of

A

high vacuum

100
Q

The __________ of the fluid contained in the temperature sensing element (i.e., bulb) of filled system thermometers changes with change in temperature.

A

all (a), (b) and (c)
(pressure
volume
viscosity)

101
Q

__________ thermometer can not measure sub-zero (< 0° C) temperature,

A

Bimetallic

102
Q

The characteristic equation for the control system with a closed loop transfer function G1/1 + G2 is given by 1 + G2 = 0. The characteristic equation for the control system

A

all ‘a’, ‘b’ & ‘c’
(depends only upon the open loop transfer function.
determines its stability.
is the same for set point or load changes.)

103
Q

Starting temperature of optical radiation pyrometer is __________ °C.

A

800

104
Q

Liquid argon level in a pressurised storage tank (at 3 kg/cm2 ) is measured by a/an

A

differential pressure gage

105
Q

An ideal PID controller has the transfer function . The frequency at which the magnitude ratio of the controller is 1, is

A

1/«(0.2 x 0.5)

106
Q

The deflection of the free end of the bimetallic strips in a bimetallic thermometer with temperature is nearly

A

linear

107
Q

Alphatron measures pressure __________ microns.

A

> 3

108
Q

What is the ratio of output amplitude to input amplitude for a sinusoidal forcing function in a first order system ?

A

< 1

109
Q

The unit step response of the transfer functionreaches its final steady state assymptotically after

A

a monotonic increase

110
Q

The term analogous to the electrical current in a thermal system is the

A

heat flow rate

111
Q

Reset rate is the another term used for __________ time.

A

integral

112
Q

Continuous measurement of moisture in paper is done by

A

high resistance Wheatstone’s bridge circuit

113
Q

Psychrometer determines the

A

humidity of gases

114
Q

A mercury barometer measures the __________ pressure.

A

atmospheric

115
Q

Positioning controllers are used for

A

high loads

116
Q

The amplitude ratio for the sinusoidal response of a __________ is 1.

A

transportation lag

117
Q

The response of two tanks of same size and resistance in series is

A

critically damped

118
Q

The amplitude ratio for the sinusoidal response of __________ is < 1.

A

first order system

119
Q

Which of the following is a ‘contact’ pyrometer ?

A

resistance pyrometer

120
Q

Which of the following is not a speed measuring instrument ?

A

Psychrometer

121
Q

Measurement of sub-zero Celcius temperature in industry is done most commonly by

A

resistance thermometers

122
Q

Use of I-control along with P-control facilitates

A

elimination of offset

123
Q

Turbine flow meters are suitable for

A

both
(cryogenic flow measurements.
aerospace and in air borne applications.)

124
Q

Liquid discharge from a tank or reservoir can not be measured by

A

orificemeters

125
Q

Which of the following is not a mechanical pressure sensing element ?

A

U-tube

126
Q

__________ are analysed using a polarograph.

A

Solids

127
Q

Which of the following judges the accuracy of an instrument ?

A

Static error

128
Q

On-off controllers are normally used for

A

low loads

129
Q

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

A

low electrical conductivity.

130
Q

Which of the following controllers has maximum offset ?

A

P-controller

131
Q

Pressure of 0.01 psi (absolute) can be measured by __________ gauge.

A

Mcloid

132
Q

High temperature of around 2000°C of incandescent gas mantles is measured by a/an

A

radiation pyrometer

133
Q

The unit step response of the transfer function 1/(s2 + 2s + 3)

A

has a damped oscillatory characteristics

ChELE Concept (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions