Indicate whether the following statements are True or False. Motivate all your
answers.
1. Non-proportional test piece is a test piece having a gauge length specifically related to its cross-sectional area.

2. Sound waves are mechanical waves and thus require a medium that functions as a carrier

3. The most important of all the echo methods, and at the same time of all the ultrasonic testing methods is the pulse-echo method

4. By definition, a sound field has boundaries

5. The gamma ray-method is similar to an X-ray examination and uses rays emanating from such radioactive substances as radium or gas from radium