NDT - Non-Destructive Testing Ultrasonic Testing Principles Questions and Answers

Question 1

In ultrasonic testing, what is the primary purpose of using a couplant between the transducer and the test specimen?

Accepted Answer

To eliminate the air gap and facilitate the transmission of sound energy.

Answer

To lubricate the surface for smooth transducer movement.

Answer

To protect the transducer from wear and tear.

Answer

To increase the acoustic impedance of the test material.

Question 2

Which of the following best describes the principle of acoustic impedance in the context of ultrasonic testing?

Accepted Answer

It is a measure of the material's resistance to the propagation of sound waves, calculated as density times velocity.

Answer

It is the frequency at which the material resonates when subjected to ultrasonic waves.

Answer

It is the total distance an ultrasonic wave can travel before its amplitude is reduced by half.

Answer

It is the angle at which sound is reflected from an interface.

Question 3

A technician is performing an angle beam inspection on a steel weld. The ultrasonic wave travels from a plastic wedge into the steel. According to Snell's Law, what will happen to the sound wave as it enters the steel?

Accepted Answer

The wave will bend or refract at an angle determined by the velocities in the two materials.

Answer

The wave will convert entirely into a surface wave.

Answer

The wave will maintain the same angle of propagation.

Answer

The wave's frequency will increase, and its velocity will decrease.

Question 4

In ultrasonic testing, which wave mode has particle motion perpendicular to the direction of wave propagation and cannot travel through liquids or gases?

Accepted Answer

Shear waves

Answer

Longitudinal waves

Answer

Rayleigh waves

Answer

Lamb waves

Question 5

When increasing the frequency of the transducer in an ultrasonic test, what is the expected effect on the inspection's sensitivity and wavelength?

Accepted Answer

Sensitivity increases and wavelength decreases.

Answer

Sensitivity decreases and wavelength increases.

Answer

Sensitivity decreases and wavelength decreases.

Answer

Sensitivity increases and wavelength increases.

Question 6

A technician is inspecting a large casting with access to only one side. The goal is to detect internal voids. Which ultrasonic testing technique is most appropriate for this scenario?

Accepted Answer

Pulse-echo

Answer

Through-transmission

Answer

Immersion testing

Answer

Phased array