Free NDT Ultrasonic Testing Questions and Answers

Question 1

In a specific substance, the sound speed is:

Accepted Answer

Is constant

Answer

The speed of sound in a specific homogeneous material is a fundamental and constant property of that material under given conditions, such as temperature. It does not change with distance from the transducer or other factors during an ultrasonic test. This consistent speed is crucial for accurate distance measurements and flaw location in ultrasonic testing.

Question 2

The reflective surface of the discontinuity must have a diameter at least as long as ________ wavelength in order to provide a fair chance of being detected.

Accepted Answer

One-half

Answer

For reliable detection of a discontinuity using ultrasonic testing, the reflective surface of the discontinuity should ideally have a diameter at least as long as one-half of the wavelength of the ultrasonic wave. If the discontinuity is significantly smaller than half a wavelength, the sound wave tends to diffract around it, making detection difficult or impossible and reducing inspection sensitivity.

Question 3

The term for the combined impact of absorption and dispersion is:

Accepted Answer

Attenuation

Answer

Attenuation is the term used to describe the decrease in the intensity of a wave as it propagates through a medium. This phenomenon is a combined result of absorption, where the material converts wave energy into other forms like heat, and dispersion (or scattering), where the wave energy is redirected in various directions. Therefore, attenuation directly represents the overall loss of wave energy due to these two effects.

Question 4

The capacity to identify a tiny discontinuity is known as:

Accepted Answer

Sensitivity

Answer

In Non-Destructive Testing, sensitivity refers to the system's ability to detect the smallest possible discontinuity or defect within a material. A highly sensitive test can identify very minute flaws, which is crucial for ensuring material integrity. This differs from resolution, which is the ability to distinguish between two closely spaced discontinuities.

Question 5

At a depth of roughly: Surface waves, also known as Rayleigh waves, travel along the surface of relatively thick solid materials.

Accepted Answer

One wavelength

Answer

Rayleigh waves, also known as surface waves, propagate along the surface of a material. Their energy is largely confined to a shallow depth below the surface. Specifically, the significant energy of a Rayleigh wave is typically concentrated within approximately one wavelength of the surface, making them ideal for detecting surface and near-surface discontinuities.

NDT - Non-Destructive Testing Practice Test

NDT - Non-Destructive Testing Practice Test

Free NDT Ultrasonic Testing Questions and Answers