Lesson 2 Quiz UT Flashcards
- By changing the transducer, the ultrasonic testing technician could change the testing:
Frequency, Different transducers operate at different frequencies, so by changing the transducer, the technician can alter the frequency used during the test.
- Another name for a longitudinal wave is:
Compression Wave, Longitudinal waves are also known as compression waves because they cause particles in the material to compress and expand in the direction of wave propagation.
- The velocity of a longitudinal wave is:
About twice the velocity of a shear wave in steel, Longitudinal waves travel faster than shear waves. In steel, the velocity of longitudinal wave is approximately twice that of a shear wave.
- Surface waves travel at about 10% less than:
Shear waves, Surface waves travel slightly slower than shear waves, which are transverse waves that propagate within a material.
- In ultrasonic testing, the term attenuation is closely connected to:
Damping, Attenuation refers to the reduction in amplitude or intensity of the sound wave as it travels through the material, which is closely linked to damping.
- When wave energy is lost through reflection and scattering of the beam within the material, it is understood that _______ is occurring.
Attenuation, Attenuation occurs when wave energy decreases due to scattering, reflection, or absorption as the wave travels through a material.
- The opposition of a material to the passage of a sound wave is called:
Acoustic impedance, Acoustic impedance is the resistance a material presents to the passage of a sound wave. It is a function of the material’s density and sound velocity.
- Acoustical impedance of a given material is derived by material density:
Multiplied by sound velocity, Acoustic impedance is the product of the material’s density and the velocity of sound throuth the matierial. It is a key factor in determining the reflection and t6ransmission of sound at interfaces.
- The higher the ratio of acoustic impedance, the:
Mismatch, An impedance mismatch occurs when two materials have very different acoustic impedances, causing more reflection of sound waves at all boundrary.
- A higher impedance ratio is often called impedance:
Mismatch, An impedance mismatch occurs when two materials have very diffrent acoustic impedances, causing more reflection of sound waves at the boundary.
- In ultrasound, the term refraction refers to _________ of the sound beam as it passes from one medium to another.
Bending, Refraction refers to the change in direction (or bending) of a sound wave as it passes from one medium to another with a diffrent veloci8ty of sound.
- Refraction and mode conversion occur because the _________ of the longitudinal wave changes as the beam enters the second medium.
Speed, The speed of the wave changes when it enters a medium with a different density and elastic properties, causing refraction and potentially mode converasation.
- The velocity of shear waves is approximately ___________ that of compression waves.
Half, Shear waves typically travel at around half the speed of longitudinal (compression) waves in the same material.
- Snell’s law can be used to calculate angular relationships and :
Velocity measurements, Snell’s law relates the angles of incidence and refraction to the velocities of waves in different media, allowing for the calculatioon of wave velocity changes between materials.
- The relative amount of ultrasonic energy transmitted through a solid boundary interface in a test object depends primarily on:
The relative acoustic impedances of the materials on either side of the interface, The amount of energy transmitted or reflected at a boundary between two materials depends on the difference intheir acoustic impedances.
- The point at which the longitudinal wave refracts to 90 degrees is called the _______ angle.
First critical, The first critical angle is the angle of incidence where the refracted longitudinal wave propagates along the surface at 90 degrees.
- The region between normal incidence and the first critical angle is not very useful for ultrasonic testing purpose because:
The presence of two beams results in confusing reflections, In this region, both longitudinal and shear waves can coexist, leading to overlapping and confusing reflections, making it difficult to interpret results.
