1. KARPAGAM INSTITUTE OF TECHNOLOGY
COIMBATORE - 105
DEPARTMENT OF MECHANICAL ENGINEERING
Academic Year: 2020 - 2021 (ODD Semester)
MCQ Test UNIT III
Subject Code & Name : ME8097 –Non Destructive Testing and Evaluation
PART A
1
___________ testing technique allows the visualization of heat patterns on an
object
a) Thermography
b) thermal imaging
c) infrared thermography
d)All of the above
2
The temperature differences observed on the investigated surface during inspection
will be monitored by __________ camera
a) An infrared
b) Thermal
c) Both a and b
d) None of the above
3
Which of the following is not the characteristics of infrared ?
a)It is sometime called as “heat ray”
b) Its wavelength is larger than the visible light
c) It’s a kind of electromagnetic wave
d)It cannot travel through vacuum
4
_________ is the distance between successive crest of a wave , especially in an
electromagnetic wave.
a) Speed of light
b) Frequency
c) Wavelength
d)None of the above
5
The relationship between wavelength and frequency for electromagnetic wave is
a) v=c/λ
b) λv=c
c) λ=c/v
d) All of the above
6
An object which has the ability to radiate the maximum possible energy for its
temperature is known as
a) Black body
b) Thermal body
2. c) Emit body
d)None of the above
7
Emissivity is defined as
a) Hobject+Hblackbody
b) Hobject/Hblack body
c) Hblack body/ Hobject
d)H black body+ Hobject
8
Є= 1 signifies that the body is a _____________ body
a)Perfect black body
b) Black body
c)Both a and b
d)None of these
9
Which of the following is an advantage of thermography testing
a) The thermography device is risk as it emits radiation
b) This technique is very slow
c) This technique can create a thermal image
d)This technique is not effective
10
Medium wave infrared is
a) 8-14 µm
b) 3-6 µm
c) 2-3 µm
d)3-5 µm
11
Long wave infrared is
a) 8-14 µm
b) 3-6 µm
c) 10-13 µm
d)8-15 µm
12
The output from the IR camera is a grey scale image .That image is also known as
a) IR image
b) Thermogram
c) Color image
d)None of the above
13
IR light has a range of wavelength that ranges from
a) Red to blue
b) Yellow to blue
c) Red light to violet
d)Red to green
14
Infrared waves ranges from
a) 0.75 to 10000 µm
b) 0.65 to 10000 µm
c) 0.55 to 1000 µm
d)0.75 to1000µm
15
Which of the following is not the basic elements of infrared detection system?
a) IR detectors
b) Sensor
c) Optical components
3. d)Signal processing
16
Vibro thermography is also known as
a) Pulsed thermography
b) Lock in thermography
c) Modulated thermography
d)ultrasound thermography
17
Stephans Law of Radiation is
a) 𝐻 = 𝜎T3
b) 𝐻 = 𝜎T2
c) 𝑯 = 𝝈T4
d) 𝐻 = 𝜎T14
18
The body follows the Stephens law is termed as
a) hot body
b)Black body
c) Both a and b
d)None of these
19
In __________ thermography, a burst of ultrasonic waves are injected into the test
specimen for a short time and it varies from milliseconds to few seconds.
a) Modulated
b) Pulsed
c) Lock in
d)Burst Vibro
20
The ____________ works on the basis of electromagnetic induction.
a) Thermography testing
b) Eddy current testing
c) Vibro thermography testing
d)Lock in thermography
21
Eddy currents are created through a process called
a) Electrostatic induction
b) Electromagnetic induction
c) Both a and b
d)None of the above
22
The main function of the low pass filter(LPF) is to remove _____ frequency
interference noise
a) High
b) low
23
The main function of the high pass filter (HPF) is to remove _____ frequency
interference noise
a) High
b) low
24
Which of the following factors are not influenced by eddy current testing?
a) Permeability
b) frequency
c) Material conductivity
d)None of the above
4. 25
________ May be defined as the ease with which a material can be magnetized.
a) frequency
b) Conductivity
c) Permeability
d)Design
26
The distance between a surface coil and the test surface is called as ________
a) Lift off
b) Proximity
c) Both a and b
d)None of the above
27
Eddy current testing is performed within a frequency range of ________
a) 70Hz to 100MHz
b) 50Hz to 100MHz
c) 60Hz to 20MHz
d)50Hz to 10MHz
28
___________ are magnetic field transducer that exhibit a linear change in electric
resistance under an external magnetic field.
a) SQUID devices
b) Hall effect sensors
c)Magneto resistive sensors
d) All of the above
29
___________ can detect magnetic fields from eddy currents and can be used in
eddy current testing.
a) SQUID devices
b) Hall effect sensors
c)Magneto resistive sensors
d) All of the above
30
___________ device are designed to measure extremely weak magnetic fields.
a) SQUID devices
b) Hall effect sensors
c)Magneto resistive sensors
d) All of the above
31
A variation of eddy current testing is remote field eddy current testing is also called
as
a) Send probe technique
b) Send- receive probe technique
c) Both a and b
d)None of these
32
The basic elements involved in eddy current testing system are
a) Oscillator
b) Test coil
c) Both a and b
d)None of the above
33
Skin effect impact penetration depth and the ability of eddy currents t detect defects
a)True
b) False
5. 34
______ is the shift in time between the eddy current response from a disruption on
the surface and a disruption at some distance below the surface.
a) Phase lag
b)Skin effect
35
What is the advantage of magneto resistive sensors?
a) Expensive
b) Complex in construction
c) Macro size
d)High sensitivity
PART B
1
In Stephan’s law of Radiation ,the value of proportionality constant σ is
a) 4.67x10-8
wm-2
k-4
b) 3.77x10-8
wm-2
k-4
c) 5.67x10-8
wm-2
k-4
d)6.67x10-8
wm-2
k-4
2
“A body radiates heat per unit area per unit time is proportional to the fourth power
of its absolute temperature” which law states this?
a) Planck’s radiation law
b) Weins displacement law
c) Stephan’s law of Radiation
d)None of these
3
In Planks Radiation Law the value of planks constant h is
a) 4.625x10-27erg-sec
b) 5.625x10-27erg-sec
c) 3.625x10-27erg-sec
d)6.625x10-27erg-sec
4
The value of Boltzman constant k is
a) 2.38x 10-16erg/°k
b) 1.38x 10-16erg/°k
c) 4.38x 10-16erg/°k
d)3.38x 10-16erg/°k
5
___________ law relate the fundamental electrical quantity voltage and current.
a) Planck’s radiation law
b) Lenz law
c) Ohms law
d) Weins displacement law
6
______is one of the properties measured in eddy current testing
a) Planck’s radiation law
b) Lenz law
c) Ohms law
d) Weins displacement law
7
Which of the following is not the advantage of eddy current?
a) Physical contact required
b)Low cost
c) Portable
6. d)complex shape can be inspected
8
In __________ technique energy source are used to pulse heat the specimen
surface.
a) Thermography testing
b) Vibro thermography testing
c)Lock in thermography
d) Pulsed thermography
9
In _____ technique ,the specimen surface is periodically illuminated by modulated
heating source like halogen lamps ,to injet thermal waves in to the specimen.
a) Lock in thermography
b) Modulated thermography
c) Both a and b
d)None of the above
10
The application of lock in Thermography is
a) Corrosion detection
b) Determination of coating thickness
c) Determination of impact damages on CFRP panels.
d)Both a and b
11
____________ magnetic material has a relative magnetic permeability slightly
greater than 1
a) Para magnetic material
b) Dia magnetic material
c) Ferro magnetic material
d)None of the above
12
____________ magnetic material has a relative magnetic permeability slightly less
than 1
a) Para magnetic material
b) Dia magnetic material
c) Ferro magnetic material
d)None of the above
13
____________ magnetic material has a relative magnetic permeability much
greater than 1
a) Para magnetic material
b) Dia magnetic material
c) Ferro magnetic material
d)None of the above
14
_______ sensor can detect magnetic fields from currents and can be used in eddy
current testing
a) Hall effect sensor
b) Spin valve sensor
c) Magnetic tunnel junction sensor
d)None of the above
15
Whenever relative motion occurs between a metal conductor and magnetic lines of
force ,electrical currents are induced in the surface of the metal conductor .These
induced electric current called as
