Heat-resistant ceramic tiles line the inside of a furnace. An ultrasonic probe is placed against the exposed surface of a tile. The probe records the time between sending a pulse and receiving its reflection from the rear surface.
A reference tile made from the same ceramic is used to calibrate the probe.
| measurement | tile thickness / mm\text{mm}mm | echo time / μs\mu\text{s}μs |
|---|---|---|
| reference tile | 20.0 | 12.5 |
| tile being inspected | unknown | 9.6 |
The tile being inspected was 18.0 mm thick when it was installed.
Calculate the current thickness of the tile being inspected in mm\text{mm}mm.
The maintenance team wants to use the echo time to decide whether a tile needs replacing. A tile must be replaced when its thickness is less than 88% of its installed thickness.
Determine whether the tile being inspected must be replaced. Use the measurements to support your answer.