Process Control and Instrumentation Flashcards by Kris Daclan

Which of the following is an undesirable dynamic characteristic of an instrument ?
Reproducibility
Dead zone
Time lag
Static error

Time lag

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Which of the following is not the triple point of water ?
32°R
273°K
492°R
32°F

32°R

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

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

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Load cells are used for the measurement of
stress
weight
strain
velocity

weight

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Which of the following is the dynamic characteristics of an instrument ?
Reproducibility
Sensitivity
Dead zone
Fidelity

Fidelity

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

CO2 is the strongest paramagnetic gas.

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The __________ of a vapor pressure thermometer is a functioning element.
pointer
bourdon tube
bulb
none of these

pointer

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A negative gain margin expressed in decibels means a/an __________ system.
stable
unstable
critically damped
none of these

unstable

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

solid semi-conductor

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Flapper nozzle is used in a/an __________ controller.
electronic
hydraulic
pneumatic
none of these

pneumatic

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Typical specifications for design stipulates the gain margin and phase margin to be respectively
> 1.7 and > 30°
< 1.7 and > 30°
< 1.7 and < 30°
> 1.7 and < 30°

> 1.7 and > 30°

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Working principle of radiation pyrometer is based on the
Wien’s law
Kirchoffs law
Stafan-Boltzman law
Seebeck effect

Stafan-Boltzman law

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

Thomson effect

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

Fahrenheit

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

R/(TS + 1)

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

High fidelity

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

variable flow area.

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

iron-constantan

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

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

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

Radiation/infrared pyrometer

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Thermal conductivity measurement com-prises the working principle of a
CO2 analyser
polarimeter
spectrometer
chromatograph

CO2 analyser

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Response of a system to a sinusoidal input is called __________ response.
impluse
unit step
frequency
none of these

frequency

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he closed loop pole of a stable second order system could be
both real and positive.
complex conjugate with positive real parts.
both real and negative.
one real positive and the other real negative.

both real and negative.

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Smoke density of the flue gas going out of the chimney is measured by a
polarograph
thermal conductivity meter
photo electric cell
chromatograph

photo electric cell

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Transfer function of transportation lag is e^TS e^-TS 1/(Ts+1) none of these

e^-TS

Temperature measuring instruments are standardised mostly with __________ points of pure substances. melting boiling both (a) & (b) neither (a) nor (b)

both (a) & (b)

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

Mercury in glass thermometer kept in boiling water.

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

500

Which of the following controllers has the least maximum deviation ? P-controller P-I controller P-I-D controller P-D controller

P-D controller

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

mercury in glass

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

All (a), (b) & (c)

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

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

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

oxygen in

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

both (a) and (b)

The transfer function for a PID controller is (where, τ i is the integral (reset) time and τD is the derivative time.) Kc(1 + τis + τD ). s Kc(1+1/τis + τDs) Kc(1+τis + 1/τDs) Kc(1+1/τis + 1/τDs)

Kc(1+1/τis + τDs)

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

an isotope

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

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

Nichol's chart deals with A.R.vs. phase lag of first order. A.R. vs. phase lag of second order. closed loop values vs. open loop values. frequency response values of controllers.

closed loop values vs. open loop values.

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

Chromel-constantan.

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

Kc is reduced.

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

Non-linear relation of emf to temperature

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

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

For an input forcing function, X(t) = 2t2, the Laplace transform of this function is 2/s^2 4/s^2 2/s^3 4/s^3

4/s3

Continuous shell temperature measurement in a liquid-liquid heat exchanger is done by a thermocouple reistance thermometer mercury in glass thermometer vapor pressure thermometer

thermocouple

The __________ of a vapor pressure thermometer is a secondary element. pointer Bourdon tube bulb none ofthese

Bourdon tube

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

platinum-platinum+rhodium

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

Peltier effect

The second order system with the transfer function 4/(S^2 +2S+4) has a damping ratio of 2.0 0.5 1.0 4.0

0.5

In a shell and tube heat exchanger, the flow rate of heating/cooling fluid is the __________ variable. load controlled manipulated none of these

manipulated

A non-linear chemical system is exemplified by a/an isothermal CSTR mixer non-isothermal CSTR none of these

non-isothermal CSTR

The transfer function for an ideal proportional plus reset controller (reset time T) is Kc(1+1/TS) Kc(1 + TS) Kc/(1+TS) Kc/(1+S/T)

Kc(1+1/TS)

The frequency response of a first order system, has a phase shift with lower and upper bounds given by - ∞, π/2 -π/2, π/2 -π/2, 0 0, π/2

0, π/2

Gas chromatography is used for the measurement of temperature pressure concentration flow rate

concentration

Which of the following thermocouples can measure the maximum temperature ? Platinum-rhodium Tungsten-molybdenum Chromel-alumel Iron-constantan

Tungsten-molybdenum

Radiation pyrometers as compared to thermocouples has a slower speed of response. can measure higher temperature. can't measure the temperature of moving objects. is more affected by corrosive atmosphere.

can measure higher temperature.

Liquid flow rate in a small channel is best measured by a/an weir pitot tube vane meter venturimeter

pitot tube

Specific gravity of a liquid can not be measured by a/an anemometer specific gravity bottle pycnometer hydrometer

anemometer

__________ temperature scale assigns 0° to the 'ice point' and 80° to the 'steam point'. Celcius Rankine Reumur Farenhite

Reumur

Dead zone is the same as time constant. same as transportation lag. maximum change in the variable that does not change the reading of the instrument. none of these.

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

Which of the following thermometers is not suitable for distant reading upto 60 metres? Vapor pressure thermometer Mercury in glass thermometer Constant volume gas thermometer Resistance thermometer

Mercury in glass thermometer

Degree to which an instrument indicates the changes in measured variable without dynamic error is called its speed of response reproducibility fidielity static characteristics

fidielity

Thermistors are made of ultra pure metals metal oxides iron-copper alloys nickel-chromium alloys

metal oxides

A barometer measures the __________ pressure. absolute gauge absolute as well as gauge dynamic

absolute

Humidity of air can be determined by a chromatograph sling psychrometer mass spectrometer polarimeter

sling psychrometer

Thermocouple in a thermal well behaves as a true first order system. second order system (overdamped). multiple first order system. second order system (underdamped).

multiple first order system.

The transfer function for a P-D controller is Kc(1+τD s) Kc(1 +1/τD s) Kc τD s Kc/τD s

Kc(1+τD s)

Bode diagram is a plot of log (AR) vs. log (f) and (Φ) vs. log (f). log (AR) vs. f and log Φ vs.f. AR vs. log (f) and Φ vs. log (f). none of these.

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

Working principle of disappearing filament type optical pyrometer is based on the Wien's law Seebeck effect Kirchoff's law Peltier effect

Wien's law

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. no change decrease increase exponential decrease

increase

Pick out the wrong statement Proportional controller is normally used for level control in industrial applications. CSTR can be considered as a distributed parameter system. Distributed parameter approach gives partial differential equation. Non-linear behaviour is exemplified by an on-off controller.

CSTR can be considered as a distributed parameter system.

Range of hydrogen gas constant volume themometer is __________ °C. -10 to 20 0 to 100 100 - 500 400 - 1000

0 to 100

The initial value (t=0) of the unit step response of the transfer function [(s + 1)/(2s + 1)] is 0 1/2 1 2

1/2

The __________ of a vapor pressure thermometer is a primary element. pointer Bourdon tube bulb none of these

bulb

The time constant of a first order process with resistance R and capacitance C is R + C R - C RC 1/RC

A sinusoidal variation in the input passing through a linear first order system becomes more oscillatory (frequency increases). becomes less oscillatory (frequency decreases). gets amplified (magnitude increases). gets attenuated (magnitude decreases).

gets attenuated (magnitude decreases).

Nitrogen gas constant volume thermometer is suitable for measuring a temperature of __________ °C. 0-100 < 0 > 100. > 50

> 100.

Pick out the most suitable instrument for measuring temperature in the range of-40 to 425°C. mercury thermometer bimetallic thermometer radiation pyrometer none of these

bimetallic thermometer

Accurate temperature measurement performance of a radiation pyrometer can not be affected, if the enhancement or attentuation of redia-tion occurs in the sighting path. object and surrounding are at almost the same temperature. object has varying emissivity. object is transparent.

object and surrounding are at almost the same temperature.

Relationship between absorption/evolution of heat at the thermocouple junctions and the current flow in the circuit is given by __________ effect. Peltier Thomson Seebeck none of these

Peltier

Configuration of Bourdon spring tube is never made of __________ shape. circular semi-circular helical spiral

circular

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 0° 45° 90° 180°

180°

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 overdamped response. underdamped response. undamped response. unstable response.

underdamped response.

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) V/nRT nRT/V nRT/P P/nRT

V/nRT

Measurement of pressure in ammonia reactor is done by Bourdon gauge U-tube manometer Inclined tube manometer Pirani guage

Bourdon gauge

The fluid used in hydraulic controller is water steam air oil

oil

Flow rate of a river is measured by a/an pitot tube vane meter kennison nozzle open weir

vane meter

Which of the following thermocouple materials does not contain nickel ? Alumel Chromel Constantan None of these.

None of these.

Flow rate of those fluids which are insensitive to changes in their density, viscosity or flow velocity profile can be best measured by a magnetic flowmeter pitot tube flow nozzle type flowmeter turbine flowmeter

magnetic flowmeter

Identify an unbounded input from inputs whose transfer functions are given below 1 1/S 1/S^2 1/(S^2 + 1)

1/S^2

"A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency." This is __________ criterion. Bode stability Nyquist Routh stability none of these

Bode stability

Feed forward controller accounts for the __________ changes. set point load both (a) & (b) neither (a) nor (b)

load

Which thermocouple can be used to measure a temperature of around 1400°C ? Copper-constantan Aluminium-chromel Platinum-platinum+rhodium None of these

Platinum-platinum+rhodium

Which of the following filled system expansion thermometer has the capability to measure the lowest temperature ? Mercury in glass thermometer Mercury in steel thermometer Alcohol in glass thermometer Fused metal (Na or K) in steel thermometer

Alcohol in glass thermometer

Concentration of sugar solution can be determined by the polarimetry flame photometry emission spectroscopy oscillometry

polarimetry

In a single tank system, the transfer function of __________ to inlet flow rate is 1/TS+1. outlet flow rate level both (a) & (b) neither (a) nor (b)

outlet flow rate

Which of the following can not measure a temperature of 1600°C ? Platinum resistance thermometer Thermocouple Photo-electric pyrometer Radiation pyrometer

Platinum resistance thermometer

The temperature range for which copper resistance thermometer can be used is __________ °C 0 to 150 -200 to 150 350 to 750 500 to 900

-200 to 150

Paramagnetism method is not used for the composition determination of __________ in gases. oxygen oxides of nitrogen carbon dioxide any of these

carbon dioxide

An amplitude ratio of 0.1 corresponds to __________ decibels. 20 -20 10 -10

-20

For increased speed of response of an expansion pressure spring thermometer, the thermometer bulb should have a large area but small mass. high thermal conductivity. small specific heat. all 'a', 'b' & 'c'.

all 'a', 'b' & 'c'.

Pressure of 0.0001 absolute psi can be measured by __________ gauge. Mcloid Pirani thermocouple none of these

Mcloid

Pirani gauge is used for the measurement of very high pressure. high vacuum. liquid level under pressure. liquid level at atmospheric pressure

high vacuum.

The __________ of the fluid contained in the temperature sensing element (i.e., bulb) of filled system thermometers changes with change in temperature. pressure volume viscosity all (a), (b) and (c)

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

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

all 'a', 'b' & 'c'

__________ thermometer can not measure sub-zero (< 0° C) temperature, Mercury in glass Bimetallic Vapor pressure Resistance

Bimetallic

Starting temperature of optical radiation pyrometer is __________ °C. 800 400 1200 1500

800

Liquid argon level in a pressurised storage tank (at 3 kg/cm2 ) is measured by a/an gage glass external float gage differential pressure gage none of these

differential pressure gage

Which of the systems having following transfer functions is stable? 1/(s2+ 2) 1/(s2-2s + 3) 1/(s2 + 2s + 2) exp(-20s)/(s2 + 2s-l)

1/(s2 + 2s + 2)

What is the dynamic error in a critically damped second order instrument for a ramp input (At) ? 0.5 AT 2 AT √AT 1.5 AT

2 AT

An ideal PID controller has the transfer function [1+1/0.55 + 0.25]. The frequency at which the magnitude ratio of the controller is 1, is 0.5/0.2 0.2/0.5 0.2 x 0.5 1/√(0.2 x 0.5)

1/√(0.2 x 0.5)

The deflection of the free end of the bimetallic strips in a bimetallic thermometer with temperature is nearly linear non-linear parabolic hyperbolic

linear

Alphatron measures pressure __________ microns. < 1 < 3 > 3 < 0.1

> 3

What is the ratio of output amplitude to input amplitude for a sinusoidal forcing function in a first order system ? 1 >1 < 1 none of these

< 1

The unit step response of the transfer function (2s-1)/[(3s+1)(4s+1)] reaches its final steady state assymptotically after a monotonic increase. a monotonic decrease. initially increasing and then decreasing. increasing decreasing and then increasing.

a monotonic increase.

A process is initially at steady state with its output y=l for an input u=l. The input is suddenly changed to 2 at time t=0. The output response is y(t)=1+2t. The transfer function of the process is 2/s 1+2/s^2 1+2/s 1/s * (1+2/s)

1/s * (1+2/s)

The term analogous to the electrical current in a thermal system is the temperature difference heat flow rate heat content in the system none of these

heat flow rate

Reset rate is the another term used for __________ time. dead integral derivative none of these

integral

Continuous measurement of moisture in paper is done by sling psychrometer. hair-hygrometer. weighing. high resistance Wheatstone's bridge circuit.

high resistance Wheatstone's bridge circuit.

Psychrometer determines the humidity of gases moisture content of solids water of crystallisation hygroscopic nature of solids

humidity of gases

A mercury barometer measures the __________ pressure. atmospheric gauge vacuum absolute

atmospheric

Positioning controllers are used for low loads temperature changes high loads flow rate changes

high loads

The amplitude ratio for the sinusoidal response of a __________ is 1. first order system second order system transportation lag none of these

transportation lag

The response of two tanks of same size and resistance in series is under damped critically damped over damped none of the above

critically damped

The amplitude ratio for the sinusoidal response of __________ is < 1. transportation lag first order system second order system none of these

first order system

Which of the following is a 'contact' pyrometer ? resistance pyrometer optical pyrometer radiation pyrometer infra red pyrometer

resistance pyrometer

Which of the following is not a speed measuring instrument ? Psychrometer Stroboscope Tachometer All (a), (b) and (c)

Psychrometer

Measurement of sub-zero Celcius temperature in industry is done most commonly by thermocouples resistance thermometers gas thermometers bi-metallic thermometers

resistance thermometers

Use of I-control along with P-control facilitates elimination of offset reduction of offset reduction of stability time none of these

elimination of offset

Liquid discharge from a tank or reservoir can not be measured by orificemeters weirs mouthpieces notches

orificemeters

Which of the following is not a mechanical pressure sensing element ? Bellows Diaphragm Bourdon tube U-tube

U-tube

__________ are analysed using a polarograph. Isotonic solutions Solids Liquids Gases

Solids

Which of the following judges the accuracy of an instrument ? Dead zone Drift Static error None of these

Static error

On-off controllers are normally used for low loads temperature changes flow rate changes none of these

low loads

Magnetic flowmeters are generally not used for the velocity/flow measurement of hydrocarbons due to their low thermal conductivity. low electrical conductivity. high viscosity index. low flash point.

low electrical conductivity.

Which of the following controllers has maximum offset ? P-controller P-I controller P-D controller P-I-D controller

P-controller

Pressure of 0.01 psi (absolute) can be measured by __________ gauge. ionisation Pirani Mcloid none of these

Mcloid

High temperature of around 2000°C of incandescent gas mantles is measured by a/an specially designed thermocouple. optical pyrometer. radiation pyrometer. none of these.

radiation pyrometer.

he unit step response of the transfer function 1/(s2 + 2s + 3) has a non-zero slope at the origin. has a damped oscillatory characteristics. is overdamped is unstable

has a damped oscillatory characteristics.

The time constant of a unity gain, first order plus time delay process is 5 min. If the phase lag at a frequency of 0.2 rad/min is 60°, then the dead time (in minutes) is 5π/12 π/6 π/12 π/3

5π/12

Which of the following does not figure in the list of seven substances selected for international temperature scale ? Ice (F.P) and steam (B.P) Oxygen and sulphur (B.P) Antimony and silver (F.P) Zinc (B.P) and mercury (F.P)

Zinc (B.P) and mercury (F.P)

A constant volume gas thermometer employing __________ is used to measure sub-zero (i.e., < 0° C) temperature. helium hydrogen nitrogen none of these

helium

pH meter has one cell two cells three cells no cell

two cells

Routh test criterion provides information about the actual location of roots. cannot be used to test the stability of a control system containing transportation lag. criterion is not applicable to systems with polynomial characteristic equation. can not determine as to how many roots of the characteristics equation have positive real roots.

cannot be used to test the stability of a control system containing transportation lag.

When a bare thermocouple is covered by a protective sheath, the response becomes faster and oscillatory. faster and non-oscillatory. slower and oscillatory. slower and non-oscillatory.

slower and non-oscillatory.

What is the normal percentage of rhodium in platinum + rhodium element used in the thermocouple ? 0.1 3 13 29

Helium gas constant volume thermometer is suitable for the measurement of a temperature of __________ °C. < 100 < 0 > 0 > 800

< 0

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

Sinusoidal

Which of the following thermocouples is the most suitable for measuring a temperature of about 1600°C in an oxidizing atmosphere ? Platinum-platinum + rhodium Iron-constantan Copper-constantan Chromel-alumel

Platinum-platinum + rhodium

Mercury thermometer can be used to measure the temperature upto __________ °C. 100 250 350 750

350

The transfer function of a process is 1/(16s^2 + 8s + 4). If a step change is introduced into the system, then the response will be under damped critically damped over damped none of these

under damped

Vapour actuated pressure spring thermometer does not require ambient temperature compensation. Ambient temperature compensation is provided in gas or liquid expansion pressure spring thermometer by making the volume of thermometer bulb as large as conveniently possible. reducing the volume of the capillary to a minimum. reducing the volume of the receiving element to a minimum. all 'a', 'b' & 'c'.

all 'a', 'b' & 'c'.

Which of the following is not a differential pressure flow meter ? Rotameter Flow nozzle Orificemeter Venturimeter

Rotameter

Working principle of mercury in glass thermometer is based on volumetric expansion of mercury with increase in temperature. Which of the following undergoes minimum volumetric expansion for a given temperature change ? Water Mercury Methyl alcohal Carbon-tetrachloride

Mercury

Bourdon gauges are used for measuring pressure (kg/cm2 ) < atmospheric > 2 (gauge) < 2 (gauge) > 10 (absolute)

> 2 (gauge)

A photo electric device in which the resistance of the metal is directly proportional to the light striking on it, is known as photo-conductive cell. Photoelectric transducers are used for the measurement of those parameters, which can be used to produce variation in light intensity current flux density voltage

light intensity

A typical example of a physical system with under damped characteristic is a U-tube manometer. spring loaded diaphragm valve. CSTR with first order reaction. thermocouple kept immersed in a liquid filled thermowell.

spring loaded diaphragm valve.

An aneroid barometer measures the __________ pressure. atmospheric absolute vacuum gage

absolute

A bolometer is used for the measurement of thermal radiation. an element which senses optical input and delivers thermal output. both (a) & (b). neither (a) nor (b).

both (a) & (b).

Thermal wells are used in the temperature measurement to guard against corrosive and oxidising action on thermocouple materials reduce measuring lag. increase the fidelity. increase the sensitivity.

guard against corrosive and oxidising action on thermocouple materials

The offset introduced by proportional controller with gain Kcin response of first order system can be reduced by reducing value of Kc. introducing integral control. introducing derivative control. none of the above.

introducing integral control.

A system with a double pole at the origin is unstable since the corresponding term in the time domain is a constant. grows exponentially with time. grows linearly with time. decays linearly with time.

grows linearly with time.

To increase the speed of response of a pressure spring liquid or gas expansion thermometer, the clearance space between the thermometer bulb and the thermal well should not be filled with air a metal powder or graphite oil mercury

air

In an exothermic chemical reactor, the manipulated variable is the flow rate of coolant reactants product none of these

coolant

Very low pressure is expressed in microns(μ), which is equal to __________ mm of Hg coloumn (absolute) at 0°C. 0.0001 0.001 0.01 0.1

0.001

The inverse Laplace transform of the function fs = 1/(S*(1+S)) is 1 + e^t 1 - e^t 1 + e^-t 1 - e^-t

1 - e^-t

Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity ? CO2 N2 O2 CO

CO2

Emf generated in a thermocouple depends on the temperature of cold junction only. of hot junction only. difference between hot and cold junctions. difference between cold junction and atmospheric temperature.

difference between hot and cold junctions.

Working principle of mercury in glass thermometer is based on the __________ of mercury with increase in temperature. increase of pressure increase of thermal conductivity volumetric expansion differential linear expansion

volumetric expansion

Radiation thermometer can not measure the temperature inside a pressure vessel. of an object without coming in contact with it. of liquid oxygen. of moving objects at high temperature.

of liquid oxygen.

Temperature measurement by optical pyrometer is done above __________ point, which is 1063°C. antimony gold silver nickel

gold

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 ? CO2 O2 NO NO2

CO2

Dilatometer is used to measure stress strain deflection contraction/expansion due to changes in temperature

contraction/expansion due to changes in temperature

Mass spectrometer is used for the composition analysis of alloys solids isotopes none of these

isotopes

A first order system with a time constant of 1 min is subjected to frequency response analysis. At an input frequency of 1 radian/min, the phase shift is 45° -90° -180° -45°

-45°

__________ stability method uses open loop transfer function. Nyquist Mikhalov Ruth none of these

Nyquist

A pyranometer is an instrument used for measuring the beam radiation. global radiation. bright sunshine period. none of these.

global radiation.

All the thermocouples used for temperature measurement use dissimilar metal strips bars wires beads

wires

The transfer function of a first order system is 1/(Ts+1) 1/Ts s/(Ts+1) none of these

1/(Ts+1)

Composition of alloys can be determined by polarograph chromatograph refractrometer none of these

polarograph

Optical activity of a solution can be determined using a polarimeter polarograph dilatometer refractrometer

polarimeter

Stability of a control system containing a transportation lag can be best analysed by Routh test root locus methods frequency response methods none of these

frequency response methods

Stabilising time for the controllers is the time required for the response to reach __________ percent of its ultimate value. 63.2 87.5 95 100

Time constant is the time taken by the controlled variable to reach 63.2% of its full change. same as transportation lag. same as dead time. time required by the measured variable to reach 63.2% of its ultimate change.

time taken by the controlled variable to reach 63.2% of its full change.

Mercury manometer (U-tube type) exemplifies a __________ order system. zero first second third

second

The ratio of the largest load in a test to the original cross-sectional area of the test specimen is called the __________ stress. yield point breaking ultimate none of these

ultimate

Emf developed by a thermocouple while measuring a temperature of 400°C is 22 mV. The type of thermocouple used is chromel-alumel iron-constantan platinum-rhodium platinum-platinum+rhyodium

iron-constantan

Bode stability method uses __________ loop transfer function. open closed either (a) or (b) neither (a) nor (b)

open

Working principle of bimetallic thermometers is difference in linear co-efficient of thermal expansion of two strips of different metals welded together. Which of the following has the maximum thermal co-efficient of linear expansion? Nickel Brass Chromel Invar

Brass

Which of the following is not a second order instrument ? Mercury in glass thermometer with covering. Bare mercury in glass thermometer. Pressure gauge with one bellow, two tubes and a tank. None of these.

Bare mercury in glass thermometer.

Small furnace draught is accurately measured by an inclined tube manometer, in which the manometric liquid used most commonly is water carbon tetrachloride paraffin ethylene glycol

paraffin

Specific conductance is defined as the reciprocal of resistance in ohms of 1c.c. of liquid at a specified temperature. Its value for distilled water is about __________ micro mho/cm3. 50 100 10 1

A simple pitot tube measures the average velocity maximum velocity point velocity static pressure

static pressure

For a feed back control system to be stable, the roots of the characteristic equation should be real. poles of the closed loop transfer function should lie in the left half of the complex plane. Bode plots of the corresponding open loop transfer function should monotoni-cally decrease. poles of the closed loop transfer function should lie in the right half of the complex plane.

poles of the closed loop transfer function should lie in the left half of the complex plane.

A mercury thermometer can not be used to measure the temperature below the freezing point of mercury, which is __________ °C. -38.9 -11.9 -60.9 -80.9

-38.9

__________ controller has the maximum stabilising time. P PD PI PID

Out of the following temperature measuring instruments, the measurement accuracy will be minimum for the mercury in glass thermometer. optical pyrometer. iron-constantan thermocouple. alcohol filled thermometer.

optical pyrometer.

Stalagmometer is used for the measurement of kinematic viscosity surface tension refractive index optical activity

surface tension

The deflection in diaphragm (which is used as pressure sensor in pneumatic and electronic instruments) is dependent on the metal thickness, its diameter (d) and shape & number of corrugations. Its deflection is proportional to d d^2 d^3 d^4

d^4

Working principle of radiation pyrometer is based on the Wien's law Kirchoffs law stefan-Boltzman law Seebeck effect

stefan-Boltzman law

Liquid levels in autocalves are measued by simple float differential float type manometer glass gauge none of these

differential float type manometer

E.m.f. generated by thermocouples is of the order of _____. millivolts microvolts volts kilo volts

millivolts

A pyrheliometer is an instrument used for measuring the bright sunshine period. beam radiation. diffuse radiation. none of these.

beam radiation.

Flow rate through an orifice is __________ the pressure differential. proportional to inversely proportional to the square root of proportional to the square root of inversely proportional to the square of

proportional to the square root of

__________ is the static characteristics of an instrument, Response Tine lag Drift dynamic error

Drift

Phase lag of the frequency response of a second order system to a sinusoidal forcing function is 30° is 90° at the most approaches 180° asymptotically is 120°

approaches 180° asymptotically

Dead zone in an instrument must be less than __________ percent of the scale. 0.2 1.5 4 8

0.2

Emission spectroscopy is used for _____. solids and metal analysis. determining water purity. determination of CO2 in gases. NOxdetermination.

solids and metal analysis.

Gas analysis is commonly done using the thermal conductivity cell X-ray diffraction mass spectrometer emission spectrometer

thermal conductivity cell

The open loop transfer function of a control system is KR/(1+TS) . This represents a first order system. dead time system. a first order time lag. a second order system.

a first order system.

Thermal conductivity measurement is used for the determination of O2 percentage in the flue gas. specific gravity of petrofuels. composition of an alloy. CO2 percentage in the flue gas.

CO2 percentage in the flue gas.

Presence of a small amount of water in the organic systems can be determined by the __________ method. electrical conductivity polarimetry emission spectroscopy dielectric constant end loss factor

dielectric constant end loss factor

The transfer function of a pure dead time system with dead time τd is 1/(τ_d*s + 1) τ_d*s + 1 e^-τss e^τds

e^τds

Thermal conductivity cell is the primary element of a/an __________ analyser. oxygen carbon dioxide carbon monoxide sulphur dioxide

carbon dioxide

Zirconia probe is used for the measurement of humidity of air. % CO2 in flue gas. % O2 in flue gas. speed of a submarine.

% O2 in flue gas.

The root locus method, a pole of a transfer function G(s) is the value of s for which G(s) approaches -1 0 1 ∞

∞

__________ type of element is normally not used in the bimetallic thermometers. Flat spiral Bourdon tube Single helix Multiple helix

Bourdon tube

Suppose that the gain, time constant and dead time of a process with the following transfer function:Gc(s) = 10 exp( - 0.1s)/(0.5s + 1) are known with a possible error of ± 20% of their values. The largest permissible gain Kc of a proportional controller needs to be calculated below taking the values of process gain, time constant and dead time as 8, 0.6, 0.08 12, 0.6, 0.12 8, 0.6, 0.12 12, 0.4, 0.08

12, 0.6, 0.12

Process degree of freedom indicates __________ number of controllers to be used. the maximum the minimum both maximum and the minimum nothing about the

the maximum

Characteristic equation is the denominator of __________ loop transfer function. open closed both (a)and (b) neither (a) nor (b)

closed

Operating range of a temperature measuring instrument is 800 to 1600°C. It could be a/an __________ pyrometer. radiation optical photoelectric none of these

photoelectric

Polarograph is meant for the analysis of gaseous mixture miscible liquids solids isotopes

solids

Which of the following fluid flow measuring devices can measure the largest flow rate ? V-notch Rotameter Orificemeter Weir

Weir

In a shell and tube heat exchanger, the inlet temperature of heating/cooling fluid is the __________ variable. load manipulated controlled none of these

load

Polarisation of light forms the working principle of a _____. polarimeter polarograph chromatograph spectrometer

polarimeter

A bimetallic thermometer as compared to industrial mercury in glass thermometer has almost the same temperature measuring range (- 40°C to 450°C). accuracy (± 1% of span). speed of response. all a, b & c.

all a, b & c.

Thermal wells used in temperature measurements should have very thick walls. low emissivity. polished surface. high transmissivity of radiation.

high transmissivity of radiation.

Which of the following flow-metering instru-ments is an areameter ? Venturimeter Rotameter Pitot tube Hot wire anemometer

Rotameter

Out of the following themocouple wire insulating material, the highest temperature rating is for teflon ceramic fibre asbestos fibre glass

ceramic fibre

Which is the most suitable instrument for measuring pressure below 3 microns ? Mcleoid gauge Alphatron Ionisation gauge Bourdon guage

Ionisation gauge

Routh stability method uses __________ loop transfer function. open closed either (a) or (b) neither (a) nor (b)

closed

Pyrometry refers to the measurement of temperature with the mercurial thermometer upto 350°C. directly. which is of higher magnitude. all (a), (b) & (c).

which is of higher magnitude.

Photoelectric pyrometers are suitable in the temperature range of __________ °C. 400-1600 800-1600 800-2500 400-1000

800-1600

Non-metallic diaphragm used as pressure sensor in instruments is generally made of ____. teflon synthetic rubber bakelite thick paper

synthetic rubber

Response of a linear control system for a change in set point is called _______. frequency response transient response servo problem regulator problem

servo problem

Hot wire anemometer is used for the measurement of _____. flow rates of fluids. flow rates of granular solids. very high temperature. thermal conductivity of gases.

flow rates of fluids.

Which of the following thermocouples has the widest temperature measurement range ? Iron-constantan Chromel-alumel Copper-constantan Platinum-platinum/rhodium

Platinum-platinum/rhodium

Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are _____. air to open valve with the controller direct acting. air to close valve with the controller indirect acting. air to open valve with the controller indirect acting. air to close valve with the controller direct acting

air to open valve with the controller indirect acting.

Bourdon tube is never made of phosphor bronze monel metal stainless steel cast iron

cast iron

"An emf of the order of mV is generated when two solutions of different hydrogen ion concentration are separated by a thin glass wall". This is the working principle of a pH meter polarimeter chromatograph polarograph

pH meter

The term analogous to voltage in a single tank system is the heat content of the system. liquid volume in the tank. flow rate. level of liquid.

level of liquid.

In a shell and tube heat exchanger, the outlet temperature of heating/cooling fluid is the __________ variable. load manipulated controlled none of these

controlled

Mcleoid gauge is used to measure the point velocity flow rate vacuum pressure

vacuum

What is the Laplace transform of impulse input having magnitude 'X' ? X X2 1/X 1

Thermocouple is suitable for measuring liquid temperatures only. very high temperatures only. very low temperatures only. both high and low temperatures.

both high and low temperatures.

Bimetal strips are not used in bimetallic thermometers. thermocouples. thermostats. relays for opening & closing of electrical circuits.

thermocouples.

When the damping co-efficient (ξ) is unity, the system is Overdamped. Critically damped. Underdamped. Highly fluctuating.

Critically damped.

Nickel percentage in invar which is an iron-nickel alloy, and is used as a thermocouple material is 12 36 54 68

Silver point temperature is __________ °C. 760.5 860.5 960.5 1060.5

960.5

A non-linear system will have __________ steady state values. one more than one two three

more than one

Which of the following is not a variable area flow meter ? Piston type meter Rotameter Magnetic flow meter Orifice and tapered plug meter

Magnetic flow meter

With increase in temperature, the electrical conductivity of the platinum used in the resistance thermometer increases decreases remains constant increases exponentially

decreases

Sub-zero temperature (< 0°C) can be measured by a constant volume gas thermometer employing _____. helium nitrogen hydrogen none of these

helium

_________ is an example of distributed parameter system Tubular reactor CSTR On-off controller none of these

Tubular reactor

Which of the following is not classified as a thermo electric pyrometer ? Resistance thermometer. Thermocouple. Optical pyrometer (disappearing filament type) Radiation pyrometer

Optical pyrometer (disappearing filament type) Because it is a non-contact instrument.

Maximum differential pressure in liquid manometer is __________ psi. 20 30 40 50

Phase margin is equal to _____. 180° - phase lag phase lag - 180° phase lag + 180° phase lag + 90°

180° - phase lag

Flow rate measurement of hostile acids and alkalis can be most suitably done by a/an venturimeter orificemeter magnetic flow meter hot wire anemometer

magnetic flow meter

Compositional analysis of flue gas coming out of a furnace in respect of O2 and CO2% can be continuously done by a/an orsat apparatus thermal conductivity cell zirconia probe chromatograph

thermal conductivity cell

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

semi conductors

The pressure sensing element of elastic type pressure gauge is never made in the form of a bellow diaphragm strip Bourdon tube

strip

Liquid flow rate in an open channel can not be measured by a/an orifice meter cipolletti weir rectangular weir V-notch

orifice meter

The unit of 'time constant' of a system is the same as that of velocity time (time)-1 none of these

time

Which of the following filled system expansion thermometers has the lowest positive temperature measurement capability ? Mercury in glass thermometer. Alcohol in glass thermometer. Fused metal (Na or K) in steel thermometer. Nitrogen in steel thermometer.

Alcohol in glass thermometer.

Liquid column manometers are used for measuring the pressure __________ kgf/cm2 . > 2(gage) < 3 (gage) < 10 (gage) < atmospheric

< 3 (gage)

Cascade control means feed forward control. more than one feed-back loop. on-off control. one feed-back loop.

more than one feed-back loop.

The level of a liquid under pressure can be determined using bubbler system differential pressure manometer diaphragm box system air-trap system

differential pressure manometer

Which of the following is never used as an element of industrial resistance thermometer ? Lead Nickel Copper 30% iron + 70% nickel

Lead

Which of the following shows maximum dip effect (indicating reverse direction of temperature change) ? Mercury thermometer Radiation pyrometer Bimetallic thermometer Thermocouple

Mercury thermometer

A stable system is the one for which the output response is bounded for all bounded input. which exhibits an unbounded response to a bounded input which satisfies the conditions for a servo problem. none of these.

for which the output response is bounded for all bounded input.

The Laplace transform of exp(at), where a > 0, is defined only for the Laplace parameter, s > a since the function is exponential. the Laplace transform of integral of exp(at) has finite values only for s > a. the Laplace transform integral of exp(at) has initial values only for s > a. the function exp(at) is piece-wise continuous only for s > a.

the Laplace transform of integral of exp(at) has finite values only for s > a.

Meleoid gauge measures the __________ pressure. positive sub-atmospheric very high atmospheric

sub-atmospheric

Which of the following thermocouples is capable of measuring a temperature of -50°C? Platinum - platinum + rhodium Chromel - alumel Iron-constantan Copper - constantan

Platinum - platinum + rhodium

Platinum resistance thermometer can be used up to antimony point which is __________ °C, and is the temperature of equilibrium between solid antimony & liquid antimony at normal atmospheric pressure. 961.93 630.74 1064.43 1261.93

630.74

Change of angle of refraction with composition comprises the working principle of a polarimeter polarograph spectrometer refractrometer

refractrometer

Which of the following instruments is not used for measuring sub-zero (<0°) temperatures ? Platinum resistance thermometer Mercury in glass thermometer Vapor pressure thermometer Radiation pyrometer

Radiation pyrometer

Which of the following is not suitable for measuring the temperature of a red hot object in the range of 800 - 1600°C ? Optical pyrometer Radiation pyrometer Photoelectric pyrometer Thermocouples

Thermocouples

Flame photometry is used for the determination of compositional analysis of solids alkali metals natural gas isotopes

alkali metals

Reference points i.e., ice point and steam point in Reaumer temperature scale are respectively - 273° & 80° 0° & 80° 32° & 460° 32° & 80°

0° & 80°

Which of the following is not a composition measuring instrument ? Thermal conductivity cell Mass spectrometer Polarograph Hot wire anemometer

Hot wire anemometer

Emf developed by a thermocouple while measuring a temperature of 800°C is about 31 mV. The type of thermocouple used is chromel-alumel iron-constantan platinum-platinum+rhodium none of these.

chromel-alumel

Which of the following thermocouples is incapable of measuring sub-zero (i.e., < 0°C) temperature ? Chromel-alumel Iron-constantan Platinum-platinum + rhodium Copper-constantan

Platinum-platinum + rhodium

Platinum resistance thermometer is the international standard for temperature measurement between triple point of hydrogen and freezing point of antimony 13.81°K to 903.9°K both (a) and (b) neither (a) nor (b)

both (a) and (b)

0n-off control which is a special case of proportional control, has a band width of about __________ percent. 100 75 25 0

The thermal emf-temperature relationship of most thermocouples is linear parabolic exponential square root

parabolic

Which is the strongest paramagnetic gas? CO2 O2 NO NO2

In Bode plot, A.R. vs. w is plotted on a/an __________ graph paper. log-lag triangular ordinary semi-log

log-lag

A first order system with unity gain and time constant τ is subjected to a sinusoidal input of frequency w = 1/τ. The amplitude ratio for this system is 1 0.5 1/√2 0.25

1/√2

For measuring the temperature of a red hot furnace, which is the most suitable instrument ? Platinum resistance thermometer Thermocouple Optical pyrometer Bimetallic thermometer

Optical pyrometer

Continuous measurement of specific gravity of a liquid is done by hydrometer contact-type electric indicators displacement meter both (a) and (c)

both (a) and (c)

Stroboscope is used for the measurement of rpm of a flywheel frequency of light depression of freezing point liquid level under pressure

rpm of a flywheel

In second order underdamped system, decay ratio = overshoot decay ratio = (overshoot)^2 overshoot increases for increasing damping co-efficient. large damping co-efficient means smaller damping.

decay ratio = (overshoot)^2

Dome temperature of blast furnace stove is most accurately measured by a radiation pyrometer. platinum-platinum/rhodium thermocuple. iron-constantan thermocouple. platinum resistance thermometer.

platinum-platinum/rhodium thermocuple.

Phase lag of the sinusoidal response of a first order system is 120° 30° 180° 90°

90°

Continuous measurement of moisture content of paper in paper industry is done by measuring the thermal conductivity through the paper electrical resistance through the paper magnetic susceptibility none of these

electrical resistance through the paper

Thermal well made of __________ gives the fastest speed of response, while measuring temperature by thermocouples. steel vycor (a glass) nichrome inconel

vycor (a glass)

Pick out the wrong statement. There is no transfer lag for a single first order system. Stirred tank with a water jacket exemplifies an interacting system. Transfer lag is a characteristics of all higher order systems (other than first order systems). Transfer lag decreases as the number of stages decreases.

Transfer lag decreases as the number of stages decreases.

Working principle of mercury in glass thermometer is volumetric expansion. pressure rise with temperature. linear expansion. none of these.

volumetric expansion.

The frequency at which maximum amplitude ratio is attained is called the __________ frequency. corner resonant cross-over natural

resonant

Which of the following can measure temperatures in the range of - 20 to 300°C ? Mercury in glass thermometer Vapor pressure thermometer Resistance thermometer None of these.

None of these.

If response of a control system is to be free of offset and oscillation, the most suitable controller is proportional controller. proportional-derivative(PD)controller. proportional-integral (PI) controller. proportional integral-derivative (PID) controller.

proportional integral-derivative (PID) controller.

A manometer measures the __________ pressure. atmospheric absolute gauge none of these

gauge

Normal mercury thermometer can be used to measure a temperature of about 300°C. However, its maximum temperature measurement range can be increased upto about 500°C by filling nitrogen under pressure in the stem. increasing the diameter of the tube. using steel tube in place of glass tube. accounting for the tube expansion.

filling nitrogen under pressure in the stem.

Minute depression of freezing point of a liquid solvent on addition of a solid solute can be best measured by a Beckman thermometer dilatometer mercury thermometer bimetallic thermometer

Beckman thermometer

Temperature of __________ can not be measured by an optical or radiation pyrometer. hot blast (air) from stoves molten slag flowing out of blast furnace combustion space in boilers rotary limestone calcination kiln

hot blast (air) from stoves

Gain margin is equal to the amplitude ratio reciprocal of amplitude ratio gain in P controller gain in P-I controller

reciprocal of amplitude ratio

In Bode plot, Φ vs ω is plotted on a/an __________ graph paper. log-log ordinary semi-log triangular

log-log

For two non-interacting first order systems connected in series, the overall transfer function is the __________ of the individual transfer functions. product ratio sum difference

product

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. 250 350 550 700

550

Mercury thermometer is commonly used for low temperature measruement. The freezing point and boiling point of mercury are respectively __________ °C. - 39 and 350 - 51 and 439 - 79 and 395 - 10 and 425

- 39 and 350

Which of the following thermocouples has the least temperature measurement range? Copper-constantan Chromel-alumel Platinum-platinum/rhodium Iron-constantan

Copper-constantan