Ultrasonics

Question 1

1	the bending of a sound beam as it passes	through an interface:
a	reflection
b	refraction	
c	attenuation
d	absorption

Answer 1

b

Question 2

2 transverse (shear) waves are described as having:
a particle motion normal (90o) to the direction
of propagation and a velocity approximately
half that of longitudinal waves
b exceptionally high sensitivity due to low
attenuation resulting from longer wavelengths when propagating through water
c a velocity approximately twice that of surface
waves in the direction of propagation
d particle motion perpendicular to the direction
of propagation and no attenuation in water

Answer 2

a

Question 3

3	a digital thickness meter uses which principle:	
a	resonance
b	pulse - echo	
c	through transmission
d	harmonics

Answer 3

b

Question 4

4 when the angle of incidence for a longitudinal wave exceeds the first critical angle
a shear wave mode will be totally reflected
b longitudinal waves will be totally reflected
:

Answer 4

b

Question 5

5 when the angle of incidence for shear wave exceeds the second critical angle we have:
a only the surface mode enters the specimen

Answer 5

a

Question 6

6 in ultrasonic testing energy is transmitted through a solid material by a series of small material
displacements within the material:
a true
b false

Answer 6

a

Question 7

7	the condition of starting at a centre position, moving toward a maximum	position, returning through the centre position to a maximum position in the opposite direction and finally returning
to the centre position is called:
a	frequency
b	period
c	cycle	
d	wavelength

Answer 7

c

Question 8

8	the back and forth movements of particles within a medium are called:	
a	cycles
b	wavelengths
c	vibrations	
d	displacements

Answer 8

c

Question 9

9	the time required to perform one complete cycle is called:
a	period	
b	frequency	
c	wavelength
d	velocity

Answer 9

a

Question 10

10	the number of cycles per second (Hz) a vibration occurs is called:
a	period
b	frequency	
c	wavelength
d	velocity

Answer 10

b

Question 11

11	a vibration can be said to have the following property:
a	cycle
b	period
c	frequency
d	all of these

Answer 11

d

Question 12

12 ultrasonic sound propagates through a medium as waves of particle vibration
a true
b false

Answer 12

a

Question 13

13 ultransonic sound is usually described as sound:
a which may or may not be heard by human ear
b too high to be heard by human ear
c too low to be heard by human ear
d which can be heard in the audible range only

Answer 13

b

Question 14

14 the velocity of sound is constant for a given material but varies from one material to another:

a true
b false

Answer 14

a

Question 15

15	ultrasonic vibrations are generally defined as having a frequency of:	
a	5 KHz
b	20 KHz	
c	100 KHz
d	1 MHz

Answer 15

b

Question 16

16 ultrasonic sound can be either continuous or pulsed:
a true
b false

Answer 16

a

Question 17

17 wavelength is described as:
a the distance a wave travels to the back surface
of the specimen
b the distance a waveform advances while a particle
makes one complete vibration or orbit
c the number of cycles produced per second
d the time required for a wave to reach a certain
point in the specimen

Answer 17

b

Question 18

18	transducers used in ultrasonic testing	exhibit which of the following:
a	ferromagnetic
b	piezoelectric	
c	electromechanical
d	hyperacoustic

Answer 18

b

Question 19

19 a definite relationship exists among the three factors; velocity, frequency and wavelength. this relationship is expressed by the formula:
a  = v/f

b  = f/v

c  = fv

d x =  /f

Answer 19

a

Question 20

20	a device that converts electrical energy to mechanical energy and mechanical	energy to electrical energy is called a:		
a	generator
b	transceiver	
c	transducer	
d	converter

Answer 20

c

Question 21

21	the zone in an ultrasonic beam where irregular intensities exist is called the:		
a	near zone	
b	far zone
c	irregular zone
d	free field

Answer 21

a

Question 22

22	the loss of energy as sound moves 	through a specimen is called:
a	absorption
b	propagation
c	reflection
d	attenuation

Answer 22

d

Question 23

23 acoustic impedance (Z) is defined as:
a the product of material density and wave velocity
b the ratio of material density to wave velocity
c the ratio of wave velocity to sound density
d the product of wave velocity and frequency

Answer 23

a

Question 24

24 the lower the impedance mismatch between materials making up an interface, the greater the sound loss:
a true
b false

Answer 24

a

Question 25

``` 25 snell's law is used to find: a critical angles b angular relationships c velocity d wavelength ```

Answer 25

a

Question 26

26 the purpose of couplant is to: a filter undersirable reflections from the specimen b tune the transducer to the correct frequency c reduce attenuation within the specimen d transmit ultrasonic waves from the transducer to the specimen

Answer 26

d

Question 27

27 the angle of reflection of an ultrasonic beam is: a equal to the angle of incidence b approximately four times the angle of incidence c approximately half the angle of incidence d equal to the angle of refraction

Answer 27

a

Question 28

28 longitudinal (compression) waves produce vibrations which are: a in the same direction as the motion of the sound b perpendicular to the motion of the sound c elliptical d symmetrical

Answer 28

a

Question 29

``` 29 in an 'A' scan presentation, the horizontal sweep (x axis) is: a elapsed time or distance b signal amplitude c distance traveled by the transducer d direction of wave travel ```

Answer 29

a

Question 30

``` 30 in the 'A' scan presentation the vertical deflection on the cathode ray tube represents: a elapsed time or distance b signal amplitude c distance travelled by the transducers d direction of wave travel ```

Answer 30

b

Question 31

``` 31 the ideal surface for ultrasonic testing is: a a rough surface b a contoured surface c an irregular or polished surface d a flat smooth surface ```

Answer 31

d

Question 32

``` 32 which of the following will not produce spurious indications: a mode conversion b attenuation c reflection d refraction ```

Answer 32

b

Question 33

33 a digital thickness meter will give a reading best described as: a the thickness of the material b the size of the defect c the distance to the area of greatest discontinuity d the distance to the back wall including the probe

Answer 33

c

Question 34

``` 34 ultrasonic testing equipment used underwater operates on which principle: a pulse - echo b through transmission c resonance d all of the above ```

Answer 34

a

Question 35

35 when using a digital thickness meter which does not have a built in system for calibration, which of the following statements is correct: a calibration is unnecessary b the meter should be calibrated once a week c the meter should be calibrated before and after every reading is taken d the meter should be check calibrated before and after every dive on which it is to be used

Answer 35

d

Question 36

36 the higher the frequency of a transducer the... a greater the beam spread and depth of penetration b less the beam spread and the greater the sensitivity and resolution c less the sound beam attenuates thus increasing penetration d less the sensitivity and the greater the penetration

Answer 36

b

Question 37

37 the acoustic impedance of an ideal couplant should be: a less than that of the transducer b higher than that of the transducer c between that of the transducer and the test specimen d irrelevant

Answer 37

c

Question 38

38 an ultrasonic test instrument that displays pulses representing the amplitude of reflected sound as a function of time and distance is a: a continuous wave b 'A' scan presentation c 'B' scan presentation d 'C' scan presentation

Answer 38

b

Question 39

``` 39 which of the following frequencies would probably result in the greatest attenuation loss? a 1.0 MHz b 10.0 MHz c 25 KHz d 25 MHz ```

Answer 39

c

Question 40

``` 40 what is a decibel: a a linear measurement of sound intensity b a logarithmic comparison c a unit of sound veloctiy d none of the above ```

Answer 40

b

Question 41

``` 41 an increase in signal amplitude of 6 dB will increase the amplitude by how many times: a 2 b 6 c 8 d 10 ```

Answer 41

a

Question 42

``` 42 an increase in signal amplitude of 20 dB will increase the amplitude by how much a 2 b 6 c 8 d 10 ```

Answer 42

d

Question 43

43 formula used to determine the near zone: a N = D2/4 lambda b N = D2 f /4 c N = D2/4f d N = D 2v/4f

Answer 43

a

Question 44

44 taking the softest sound power level the ear can detect as 1 dB what is the loudest sound the ear can accept: a 100 dB b 120 dB c 200 dB d 260 dB

Answer 44

d

Question 45

``` 45 a high frequency probe will have: a good resolution b good sensitivity c poor measuing accuracy d all of the above ```

Answer 45

a

Question 46

``` 46 when calibrating the 'A' scan unit which indication should be at full scale height: a first back wall echo b initial pulse c primary discontinuity d all peaks ```

Answer 46

a

Question 47

47 if the probe is placed over the groove on the V1 test block and three clearly defined indications are produced what can be said of the unit: a it is properly calibrated b it has good linearity c it has good sensitivity d it has good resolution

Answer 47

d

Question 48

48 when great accuracy is required in sizing a discontinuity what method should be used: a 6 dB drop b 20 dB drop c 10 dB drop d seaprobe

Answer 48

b

Question 49

49 checking the time base linearity is the term given to: a 'C' scan presentation b 'A' scan presentation c checking A scan with a digital thickness meter d checking the resolution

Answer 49

b

Question 50

50 how is the dead zone checked on a single crystal probe: a by switching to twin crystal and noting the difference b by checking the relevant tables c by measuring the length of the initial pulse c d the dead zone cannot be checked

Answer 50

c

Question 51

``` 51 UT waves in water are: a surface waves b shear waves c longitudinal waves d all of the above ```

Answer 51

d

Question 52

52 the wave length is dependent on the: a diameter of the probe b density of material under test c sound velocity and frequency d all of the above

Answer 52

c

Question 53

53 vibrations are: a chemical energy b electro/chemical energy c mechanical energy d heat energy

Answer 53

c

Question 54

54 reducing the frequency of a probe will result in: a a reduction of the attenuation b small defects will be detected more easily c penetration will be less d beam spread will be less

Answer 54

a

Question 55

55 using an 'A' scan display, a lack of parallelism will result in: a reflection that may not be indicated on the display b the most likely reflection would result in a display of numeral indications of variable amplitude c signal amplitude being greatly increased d signal amplitude being greatly reduced

Answer 55

a

Question 56

56 an inaccurate wall thickness reading will result if: a the material is laminated b there is a lack of parallelism between the back and front faces c the material is between 10 and 15 mm thick d the material is between 30 and 40 mm thick

Answer 56

b

Question 57

57 the velocity of compression waves of sound is quickest in: a steel b water c aluminium d perspex

Answer 57

a

Question 58

58 ACPD is used to: a measure the depth of a surface breaking crack b locate a sub surface defect c measure the length of a surface breaking crack d determine the width of a crack

Answer 58

a

Question 59

59 the 6 db drop is: a back wall echo to half height b back wall echo to the same height as the defect c defect half height d none of the above

Answer 59

c

Question 60

60 which has the shortest wavelength: a 25 kHz b 10 MHz c 25 MHz d 12 kHz

Answer 60

c

Question 61

``` 61 low frequency probes have: a better resolution b better penetration c higher sensitivity d all of the above ```

Answer 61

b

Question 62

``` 62 wavelength is calculated by: a velocity / frequency b frequency / velocity c velocity x frequency d velocity + frequency ```

Answer 62

a

Question 63

63 if the ultrasonic test frequency is decreased: a penetration is less b resolution is improved c attenuation decreases c d small defects detected

Answer 63

c