section 7 Flashcards
Change of angle of refraction with composition
comprises the working principle of a
a. Polarimeter
b. Polarograph
c. Spectrometer
d. refractrometer
D
Which of the following instruments is not used
for measuring sub-zero (<0°) temperatures?
a. Platinum resistance thermometer
b. Mercury in glass thermometer
c. Vapor pressure thermometer
d. Radiation pyrometer
D
Which of the following is not suitable for
measuring the temperature of a red hot object in the
range of 800 - 1600°C?
a. Optical pyrometer
b. Radiation pyrometer
c. Photoelectric pyrometer
d. Thermocouples
D
Find the Laplace transform of the following input
function shown in figure.
A
Flame photometry is used for the determination
of compositional analysis of
a. Solids
b. alkali metals
c. natural gas
d. isotopes
B
Reference points i.e., ice point and steam point in
Reaumer temperature scale are respectively
a. 273° & 80°
b. 0° & 80°
c. 32° & 460°
d. 32° & 80°
B
Which of the following is not a composition
measuring instrument?
a. Thermal conductivity cell
b. Mass spectrometer
c. Polarograph
d. Hot wire anemometer
D
Emf developed by a thermocouple while
measuring a temperature of 800°C is about 31 mV.
The type of thermocouple used is
a. Chromel-alumel
b. Iron-constantan
c. Platinum-platinum+rhodium
d. none of these.
A
Which of the following thermocouples is
incapable of measuring sub-zero (i.e., < 0°C) temperature?
a. Chromel-alumel
b. Iron-constantan
c. Platinum-platinum + rhodium
d. Copper-constantan
C
Platinum resistance thermometer is the
international standard for temperature measurement
between
a. triple point of hydrogen and freezing
point of antimony
b. 13.81°K to 903.9°K
c. both (a) and (b)
d. neither (a) nor (b)
C
On-off control which is a special case of
proportional control, has a band width of about
__________ percent.
a. 100
b. 75
c. 25
d. 0
D
The thermal emf-temperature relationship of
most thermocouples is
a. Linear
b. Parabolic
c. Exponential
d. square root
B
Which is the strongest paramagnetic gas?
a. CO2
b. O2
c. NO
d. NO2
B
In Bode plot, A.R. vs. w is plotted on a/an
__________ graph paper.
a. Log-lag
b. Triangular
c. Ordinary
d. semi-log
A
- 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
a. 1
b. 0.5
c. 1/sqrt2
d. 0.25
D
A control system has the following transfer
function FF(ss) = (ss−1)(ss+1)
ss(ss−2)(ss+4)
. The initial value of the
corresponding time function is
a. 1
b. 1⁄8
c. 7⁄8
d. -1
D
For measuring the temperature of a red hot
furnace, which is the most suitable instrument?
a. Platinum resistance thermometer
b. Thermocouple
c. Optical pyrometer
d. Bimetallic thermometer
C
Continuous measurement of specific gravity of
a liquid is done by
a. Hydrometer
b. contact-type electric indicators
c. displacement meter
d. both (a) and (c)
D
Stroboscope is used for the measurement of
a. rpm of a flywheel
b. frequency of light
c. depression of freezing point
d. liquid level under pressure
D
The root locus plot of the roots of the
characteristics equation of a closed loop system
having the open loop transfer function KK(ss+1)
2(2ss+1)(3ss+1)
will have a definite num-ber of loci for variation of
K from 0 to ∞. The number of loci is
a. 1
b. 3
c. 4
d. 2
B
- In second order underdamped system,
a. decay ratio = overshoot
b. decay ratio = (overshoot)2
c. overshoot increases for increasing damping
co-efficient.
d. large damping co-efficient means smaller
damping.
B
Dome temperature of blast furnace stove is most
accurately measured by a
a. radiation pyrometer.
b. platinum-platinum/rhodium ther-mocuple.
c. iron-constantan thermocouple.
d. platinum resistance thermometer.
B
Phase lag of the sinusoidal response of a first
order system is
a. 120°
b. 30°
c. 180°
d. 90°
D
Continuous measurement of moisture content of
paper in paper industry is done by measuring the
a. thermal conductivity through the paper
b. electrical resistance through the paper
c. magnetic susceptibility
d. none of these
B
Thermal well made of __________ gives the
fastest speed of response, while measuring
temperature by thermocouples.
a. Steel
b. vycor (a glass)
c. Nichrome
d. Inconel
B
What is the Laplace transform of sin t ?
A
Pick out the wrong statement.
a. There is no transfer lag for a single first
order system.
b. Stirred tank with a water jacket
exemplifies an interacting system.
c. Transfer lag is a characteristics of all higher
order systems (other than first order
systems).
d. Transfer lag decreases as the number of
stages decreases.
D
Working principle of mercury in glass
thermometer is
a. volumetric expansion.
b. pressure rise with temperature.
c. linear expansion.
d. none of these.
A
The frequency at which maximum amplitude
ratio is attained is called the __________ frequency.
a. Corner
b. Resonant
c. Cross-over
d. natural
B
Which of the following can measure
temperatures in the range of - 20 to 300°C?
a. Mercury in glass thermometer
b. Vapor pressure thermometer
c. Resistance thermometer
d. None of these.
D
If response of a control system is to be free of
offset and oscillation, the most suitable controller is
a. proportional controller.
b. proportional-derivative (PD)controller.
c. proportional-integral (PI) controller.
d. proportional integral-derivative (PID)
controller.
D
Conversion formula for converting amplitude
ratio (AR) into decibels is
a. Decibel = 20 log10 (AR)
b. Decibel = 20 loge (AR)
c. Decibel = 20 log10 (AR)0.5
d. Decibel = 20 loge (AR)0.5
A
A manometer measures the __________
pressure.
a. Atmospheric
b. Absolute
c. Gauge
d. none of these
C
Normal mercury thermometer can be used to
measure a temperature of about 300°C. However,
its maximum temperature measurement range can
be increased up to about 500°C by
a. filling nitrogen under pressure in the stem.
b. increasing the diameter of the tube.
c. using steel tube in place of glass tube.
d. accounting for the tube expansion.
D
Minute depression of freezing point of a liquid
solvent on addition of a solid solute can be best
measured by a
a. Beckman thermometer
b. Dilatometer
c. mercury thermometer
d. bimetallic thermometer
A
For the time domain function f(t) = t, the
Laplace transform of ∫ ff( ) tt
0 dddd is given by
a. 1/2S3
b. 2/S3
c. 1/S3
d. 2/S2
C
Temperature of __________ can not be
measured by an optical or radiation pyrometer.
a. hot blast (air) from stoves
b. molten slag flowing out of blast furnace
c. combustion space in boilers
d. rotary limestone calcination kiln
A
Gain margin is equal to the
a. amplitude ratio
b. reciprocal of amplitude ratio
c. gain in P controller
d. gain in P-I controller
B
A system with transfer function 2SS
4SS + 1 is of
__________ order.
a. Zero
b. 1st
c. 2nd
d. 3rd
B
In Bode plot, Φ vs ω is plotted on a/an
__________ graph paper.
a. Log-log
b. Ordinary
c. Semi-log
d. triangular
A
Temperature of molten pig iron (1450°C) and
molten slag (1500°C) flowing out of a blast furnace
is measured by a/an
a. chromel-alumel thermocouple
b. optical pyrometer
c. radiation pyrometer
d. either (b) or (c)
D
For two non-interacting first order systems
connected in series, the overall transfer function is
the __________ of the individual transfer functions.
a. Product
b. Ratio
c. Sum
d. difference
A
Ordinary mercury in glass thermometer is used
for measuring temperature up to 120°C. However,
for measuring higher temperature up to
__________ °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.
a. 250
b. 350
c. 550
d. 700
C
Mercury thermometer is commonly used for
low temperature measurement. The freezing point
and boiling point of mercury are respectively
__________ °C.
a. 39 and 350
b. 51 and 439
c. 79 and 395
d. 10 and 425
A
Which of the following thermocouples has the
least temperature measurement range?
a. Copper-constantan
b. Chromel-alumel
c. Platinum-platinum/rhodium
d. Iron-constantan
A
Composition of natural gas is determined by the
a. Haldane apparatus
b. mass spectrometer
c. Chromatograph
d. both (b) and (c)
D
