Unit 4

1. KARPAGAM INSTITUTE OF TECHNOLOGY
COIMBATORE - 105
DEPARTMENT OF MECHANICAL ENGINEERING
Academic Year: 2020 - 2021 (ODD Semester)
MCQ Test UNIT IV
Subject Code & Name : ME8097 –Non Destructive Testing and Evaluation
PART A
1
In ultra sound testing _________ frequency sound energy is used to identify
surface and sub surface discontinuities.
a) Medium
b) High
c) low
d)None of the above
2
ultra sound testing is applied in the inspection of weldings and structural metals,
because of its______
a) High penetration capacity
b) Low penetration capacity
c) None of the above
3
In ultrasound flaw detection most testing is carried out frequencies between
_______ and _______ cycles per second
a) 5000 to 100000
b) 50000 to 1000000
c) 500000 to 10000000
d)5000000 to 10000000
4
_________ waves travel the fastest of the wave modes and are commonly used in
ultrasonic testing of metals.
a) Longitudinal
b) shear
c) Plate
d)Surface waves
5
Which wave is used for most angle beam testing in ultrasonic flaw detection ?
a) Longitudinal
b) shear
c) Plate
d)Surface waves
6
________ wave can be used to detect surface breaking cracks in test piece.
a)Surface wave
b) Rayleigh wave
c) Both a and b

2. d)None of the mentioned
7
_________ waves are surface waves propagate parallel to the test surface and have
a particle motion that is elliptical .
a) Longitudinal
b) shear
c) Plate
d)Surface waves
8
________ is conversion of sound energy from one form to some another form.
a) Sensitivity
b) Resolution
c) Scattering
d)Absorption
9
The combined effect of scattering and absorption is called _____
a) Sensitivity
b) Attenuation
c) Scattering
d)Absorption
10
The Acoustic impedance is expressed by
a) v=ρ/z
b) ρ=zv
c) z=ρ/v
d)z=ρv
11
______ is a measure of difference of signal of defect from other back ground
signals
a) Signal to noise ratio
b) Decibel
c) Beam spreading
d)Acoustic impedance
12
Which of the following is not used as a couplant?
a) Oil
b) Kerosene
c) Grease
d) None of the above
13
In ____ method two transducers are used One is to transmit the sound waves and
other one to receive them.
a) Transmission method
b) Pulse-echo method
c) None of the above
14
The function of the transducer is to transfer ______energy to _____energy
a) Electrical to mechanical
b) Mechanical to electrical
c) Both a and b
d)None of the above
15
________ transducers are capable of generating complete range of ultrasonic
frequencies at all levels of intensities.

3. a) Laser generated ultrasound
b) Peizo-electric transducers
c) Polyvinlidene fluoride transducers
d)EMAT
16
Most of the industrial ultrasonic testing is done in the frequency ranging from
_____ to ______
a) 500 kHz to 20MHz
b) 50kHz to 20 MHz
c) 50Hz to 20 MHz
d)500 Hz to 20MHz
17
Which of the following advantages are not relate to pizeo-electric transducers
a) High frequency response
b) High output
c) Smaller in size
d)Ideal for high resolution immersion applications
18
Which of the following is called as non contact ultrasonic transducer?
a) Laser generated ultrasound
b) Peizo-electric transducers
c) Polyvinlidene fluoride transducers
d)EMAT
19
______ is a medium introduced the transducer to reduce the air gap between and
surface of the part to be inspected.
a) Transducer
b) Couplant
c) Receive
d)Amplifier
20
`Which of the following is the disadvantage of EMAT?
a) EMAT does not require couplant
b) High temperature examination is possible
c) It is a non contact transducer
d)Relatively larger in size
21
Which of the following is the advantage of EMAT?
a) Low efficiency
b) Conductive layer is to be applied on the surface
c) Focusing of the beam is possible
d)Relatively large size
22
________ is a single element transducer ,usually a longitudinal wave, that is
intended for direct contact with a test piece
a) Contact transducers
b) Dual element transducers
c) Delay line transducer
d)Immersion transducer
23
___________ consists of two longitudinal wave crystal elements –one act as
transmitter and other one act as receiver
a) Contact transducers
b) Dual element transducers

4. c) Delay line transducer
d)Immersion transducer
24
_____________ is a single element longitudinal wave transducer, whose wear face
is impedance matched
a) Contact transducers
b) Dual element transducers
c) Delay line transducer
d)Immersion transducer
25
The high frequency transducers are available in frequencies from_________
a) 20kHz to 225kHz
b) 20kHz to 225MHz
c) 20MHz to 225MHz
d)200MHz to 225MHz
26
Which of the following is not an ultrasonic inspection technique?
a) Straight beam ultrasonic inspection method
b) Angle beam ultrasonic inspection method
c) TOFD inspection method
d)Delay line inspection method
27
The angle is changed to less than 90 degrees ,longitudinal waves and second type
of sound waves are produced .These waves are called
a) Stress waves
b) Modal waves
c) Shear waves
d) None of the above
28
What is the audible range of human being
a) 30Hz to 30 KHz
b) 40Hz to 40 KHz
c) 20Hz to 20 KHz
d) 50Hz to 50 KHz
29
The wave length is ________ proportional to the velocity of the wave and _______ proportional
to the frequency of the wave.
a) Directly, Inversely
b) Inversely, Directly
c) Directly, Directly
d) Inversely, Inversely
30
Piezo Electric Transducer is a device which converts
a) Electrical to Mechanical Energy Only
b) Mechanical Energy to Electrical Only
c) Vice versa
d) None of the above
31
EMAT stands for
a) Electron Magnetic Acoustic Transducer
b) Electrical Magnetic Acoustic Transducer
c) Electro Magnetic Acoustic Transducer
d) Electrical Magnetic Acoustic Transformer
32
The divergence of an ultrasonic beam is dependent on
a) Transducer wavelength and diameter
b) Test specimen density
c) The sound wave's angle of incidence
d) The degree of damping of the ultrasonic transducer

5. 33
The piezoelectric material in a search unit which vibrates to produce ultrasonic waves
is called:
a) A backing material
b) A lucite wedge
c) A transducer element or crystal
d) A couplant
34
In ultrasonic testing, high frequency sound energy identifies surface and sub surface defects
a) True
b) False
35
Which of the following statements is/are true for ultrasonic test?
a) Equipment used for ultrasonic testing is portable
b) Complicated shapes can be easily scanned
c) Waves generated are health hazardous
d) All the above statements are true
PART B
1
The divergence of an ultrasonic beam is dependent on
a) Transducer wavelength and diameter
b) Test specimen density
c) The sound wave's angle of incidence
d) The degree of damping of the ultrasonic transducer
2
The Main Component of Acoustic Emission testing setup are
a) Sensors & Couplants
b) Amplifiers & Filters
c) Data Storage & Data Analysis
d) All of the above
3
What are the Modes of signal used in Acoustic Emission (AE)
a) Transcent Signal
b) Continuous Signal
c) (a) Alone
d) Both (a) an (b)
4
Snell’s law equation is given by
a) sinϴ1/ sinϴ2= VL1/VL2
b) sinϴ1/VL1=sinϴ2/VL2
c) VL2 /VL1= sinϴ2 /sinϴ1
d)All are correct
5
The loss of amplitude as the wave travels outwards from the source is termed as __________
a) Wave Propagation
b) Wave velocity
c) Noise
d) Attenuation
6
Transducers are selected based on ___________
a) Operating Frequency
b) Sensitivity
c) Environmental Characteristics
d) All of the above
7
The Kaiser effect describes the phenomenon that a material under load emits acoustic waves only

6. after a
a) Secondary load level is exceeded
b) Primary load level becomes zero
c) Secondary load level becomes zero
d) primary load level is exceeded
8 What can AE not be used for
a) defect location
b) defect sizing
9
What is Kaiser Effect?
a)Describes the phenomenon that a material under load emits acoustic waves only after a
previous maximum load level is exceeded
b)Appearance of significant acoustic emission at a load level below the previous maximum
applied level
10
Which of the following is/are incorrect regarding the acoustic emission technique?
i) Precise location of the defect is possible
ii) Using multiple sensors placed in a particular pattern, approximate location of the defect is
detectable
iii) Only a qualitative description of the defect is possible
a) i only
b) ii and iii only
c) i and ii only
d) all of the above
11
Detection of an acoustic emission signal depends on
a) Duration of the signal
b) Amplitude of the signal
c) Rise time of the signal
d) Frequency of the signal
12
Acoustic emission signals are classified into
a) 2 Types
b) 3 Types
c) 4 Types
d) 5 Types
13 What can AE not be used for
a) defect location
b) defect sizing
14
Acoustic energy propagates in different modes. Which of the following represent a mode?
a) Longitudinal wave
(b) Shear wave
(c) Surface wave
(d) All of the above
15
Non contact ultrasound testing frequency ranges from as low as
a) 5Hz to 1kHz
b) 50kHz to 1MHz
c) 500kHz to 1MHz
d) 50kHz to 10 MHz