NDT Study Guide & Comprehensive Non-Destructive Testing Revision Notes
When setting up a distance amplitude correction curve using 3 flat bottom holes, sometimes
the hole closest to the transducer gives less of a response than one or both of the other two.
This could be caused by: - correct answer ✔✔Near field effects
The phenomenon whereby an ultrasonic wave changes direction when the wave crosses a
boundary between materials with different velocities is called - correct answer ✔✔refraction
A circuit that generates a burst of alternating voltage that is applied to the sending transducer is
called - correct answer ✔✔Pulser
The change in direction of an ultrasonic beam when it passes from one material to another
material in which elasticity and density differ is called - correct answer ✔✔refraction
Transducers designed to generate shear waves are checked for - correct answer ✔✔All of the
above -
Depth resolution
Precise beam exit point
refraction angle
Both longitudinal and shear waves may be simultaneously generated in a second medium when
the angle of incidence is - correct answer ✔✔between normal and the first critical angle
An ultrasonic beam changes angle (refracts) when it travels from a plastic probe into a steel
specimen because - correct answer ✔✔The wave velocity is different in steel than in plastic
The amount of beam divergence from a crystal is primarily dependent on the - correct answer
✔✔Frequency and crystal size
, It should be understood that the gain control is in fact the controller of the - correct answer
✔✔amplifier circuit
When an ultrasonic beam passes through the interface of two dissimilar materials at an angle, a
new angle of sound travel takes place in the second material due to: - correct answer
✔✔refraction
When the incident angle is chosen to be be between the first and second critical angles, the
ultrasonic wave mode within the part will be a - correct answer ✔✔Shear wave
Artificial flaws can be produced by using - correct answer ✔✔All of the above-
Side drilled holes
flat bottom holes
EDM notches
The velocity of longitudinal waves is approximately _____ the velocity of shear waves in the
same material - correct answer ✔✔two times
To evaluate discontinuities that are oriented at an angle to the entry surface so that the sound
beam strikes the place of the discontinuity at right angles, the operator must - correct answer
✔✔angulate the transducer
Under most circumstances, which of the following frequencies would result in the best resolving
power? - correct answer ✔✔25 megahertz
In a liquid, the only mode of vibration that can exist is - correct answer ✔✔longitudinal
When setting up a distance amplitude correction curve using 3 flat bottom holes, sometimes
the hole closest to the transducer gives less of a response than one or both of the other two.
This could be caused by: - correct answer ✔✔Near field effects
The phenomenon whereby an ultrasonic wave changes direction when the wave crosses a
boundary between materials with different velocities is called - correct answer ✔✔refraction
A circuit that generates a burst of alternating voltage that is applied to the sending transducer is
called - correct answer ✔✔Pulser
The change in direction of an ultrasonic beam when it passes from one material to another
material in which elasticity and density differ is called - correct answer ✔✔refraction
Transducers designed to generate shear waves are checked for - correct answer ✔✔All of the
above -
Depth resolution
Precise beam exit point
refraction angle
Both longitudinal and shear waves may be simultaneously generated in a second medium when
the angle of incidence is - correct answer ✔✔between normal and the first critical angle
An ultrasonic beam changes angle (refracts) when it travels from a plastic probe into a steel
specimen because - correct answer ✔✔The wave velocity is different in steel than in plastic
The amount of beam divergence from a crystal is primarily dependent on the - correct answer
✔✔Frequency and crystal size
, It should be understood that the gain control is in fact the controller of the - correct answer
✔✔amplifier circuit
When an ultrasonic beam passes through the interface of two dissimilar materials at an angle, a
new angle of sound travel takes place in the second material due to: - correct answer
✔✔refraction
When the incident angle is chosen to be be between the first and second critical angles, the
ultrasonic wave mode within the part will be a - correct answer ✔✔Shear wave
Artificial flaws can be produced by using - correct answer ✔✔All of the above-
Side drilled holes
flat bottom holes
EDM notches
The velocity of longitudinal waves is approximately _____ the velocity of shear waves in the
same material - correct answer ✔✔two times
To evaluate discontinuities that are oriented at an angle to the entry surface so that the sound
beam strikes the place of the discontinuity at right angles, the operator must - correct answer
✔✔angulate the transducer
Under most circumstances, which of the following frequencies would result in the best resolving
power? - correct answer ✔✔25 megahertz
In a liquid, the only mode of vibration that can exist is - correct answer ✔✔longitudinal
