Q.1

Which of the following is never used as an element of industrial resistance thermometer ?

  • Nickel
  • Lead
  • Copper
  • 30% iron + 70% nickel
Q.2

Bimetal strips are not used in

  • bimetallic thermometers.
  • thermocouples.
  • thermostats.
  • relays for opening & closing of electrical circuits.
Q.3

Which of the following is not a variable area flow meter ?

  • Piston type meter
  • Rotameter
  • Magnetic flow meter
  • Orifice and tapered plug meter
Q.4

The unit of 'time constant' of a system is the same as that of

  • velocity
  • time
  • (time)-1
  • none of these
Q.5

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.
Q.6

Suppose that the gain, time constant and dead time of a process with the following transfer function:Gc(s) =exp( - 0.1s)/(0.5s +are known with a possible error of ±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
Q.7

Bourdon tube is never made of

  • phosphor bronze
  • monel metal
  • stainless steel
  • cast iron
Q.8

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
Q.9

Which of the following thermocouples is capable of measuring a temperature of -50°C?

  • Platinum - platinum + rhodium
  • Chromel - alumel
  • Iron-constantan
  • Copper - constantan
Q.10

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.
Q.11

__________ is an example of distributed parameter system

  • Tubular reactor
  • CSTR
  • On-off controller
  • none of these
Q.12

Which of the following is not a composition measuring instrument ?

  • Thermal conductivity cell
  • Mass spectrometer
  • Polarograph
  • Hot wire anemometer
Q.13

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

  • 100
  • 75
  • 25
  • 0
Q.14

Composition of natural gas is determined by the

  • Haldane apparatus
  • mass spectrometer
  • chromatograph
  • both (b) and (c)
Q.15

Which of the following shows maximum dip effect (indicating reverse direction of temperature change) ?

  • Mercury thermometer
  • Radiation pyrometer
  • Bimetallic thermometer
  • Thermocouple
Q.16

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.
Q.17

When the damping co-efficient (ξ) is unity, the system is

  • Overdamped.
  • Critically damped.
  • Underdamped.
  • Highly fluctuating.
Q.18

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

  • 12
  • 36
  • 54
  • 68
Q.19

With increase in temperature, the electrical conductivity of the platinum used in the resistance thermometer

  • increases
  • decreases
  • remains constant
  • increases exponentially
Q.20

Liquid column manometers are used for measuring the pressure __________ kgf/cm2 .

  • > 2(gage)
  • < 3 (gage)
  • < 10 (gage)
  • < atmospheric
Q.21

Cascade control means

  • feed forward control.
  • more than one feed-back loop.
  • on-off control.
  • one feed-back loop.
Q.22

"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
Q.23

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

  • dielectrics
  • insulators
  • semi conductors
  • conductors
Q.24

The pressure sensing element of elastic type pressure gauge is never made in the form of a

  • bellow
  • diaphragm
  • strip
  • Bourdon tube
Q.25

Find the ultimate gain and frequency for a proportional controller in the case of a process having the transfer function Gp(s) = 1/(4s + 1)(2s + 1)(s + 1).

  • w = 1/14, Kc = 45/714
  • w = 7/6, Kc = 46/3
  • w = 1, Kc = 13
  • w = 7/8, Kc = 45/4
Q.26

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
Q.27

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

  • load
  • manipulated
  • controlled
  • none of these
Q.28

Mcleoid gauge is used to measure the

  • point velocity
  • flow rate
  • vacuum
  • pressure
Q.29

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.
Q.30

Working principle of mercury in glass thermometer is

  • volumetric expansion.
  • pressure rise with temperature.
  • linear expansion.
  • none of these.
Q.31

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.
Q.32

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.
Q.33

Temperature of molten pig iron (1450°C) and molten slag (1500°C) flowing out of a blast furnace is measured by a/an

  • chromel-alumel thermocouple
  • optical pyrometer
  • radiation pyrometer
  • either (b) or (c)
Q.34

Which of the following is not classified as a thermo electric pyrometer ?

  • Resistance thermometer.
  • Thermocouple.
  • Optical pyrometer (disappearing filament type)
  • Radiation pyrometer
Q.35

Emf developed by a thermocouple while measuring a temperature of 800°C is aboutmV. The type of thermocouple used is

  • chromel-alumel
  • iron-constantan
  • platinum-platinum+rhodium
  • none of these.
Q.36

The thermal emf-temperature relationship of most thermocouples is

  • linear
  • parabolic
  • exponential
  • square root
Q.37

Which is the strongest paramagnetic gas?

  • CO2
  • O2
  • NO
  • NO2
Q.38

For measuring the temperature of a red hot furnace, which is the most suitable instrument ?

  • Platinum resistance thermometer
  • Thermocouple
  • Optical pyrometer
  • Bimetallic thermometer
Q.39

Platinum resistance thermometer can be used upto 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
Q.40

Gain margin is equal to the

  • amplitude ratio
  • reciprocal of amplitude ratio
  • gain in P controller
  • gain in P-I controller
Q.41

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)
Q.42

The frequency at which maximum amplitude ratio is attained is called the __________ frequency.

  • corner
  • resonant
  • cross-over
  • natural
Q.43

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.
Q.44

Conversion formula for converting amplitude ratio (AR) into decibels is

  • Decibel = 20 log10 (AR)
  • Decibel = 20 loge (AR)
  • Decibel = 20 log10 (AR)0.5
  • Decibel = 20 loge (AR)0.5
Q.45

Dome temperature of blast furnace stove is most accurately measured by a

  • radiation pyrometer.
  • platinum-platinum/rhodium ther-mocuple.
  • iron-constantan thermocouple.
  • platinum resistance thermometer.
Q.46

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
Q.47

Maximum differential pressure in liquid manometer is __________ psi.

  • 20
  • 30
  • 40
  • 50
Q.48

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
Q.49

In Bode plot, A.R. vs. w is plotted on a/an __________ graph paper.

  • log-lag
  • triangular
  • ordinary
  • semi-log
Q.50

Continuous measurement of specific gravity of a liquid is done by

  • hydrometer
  • contact-type electric indicators
  • displacement meter
  • both (a) and (c)
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