State whether true or false.

Infrasonic waves can be used to detect cracks and flaws in metallic components used in the construction of buildings.

The cracks or holes inside the metal blocks, which are invisible from the outside reduce the strength of the structure.

Ultrasonic sounds can be used to detect cracks and flaws in metal blocks. Ultrasonic waves are allowed to pass through the metal block and detectors are used to detect the transmitted waves. If there is even a small defect, the ultrasound gets reflected back indicating the presence of the flaw or defect.