Final answer:
To find the time recorded for the correct thickness of the coating using ultrasonic waves, one would first calculate the speed of sound in the coating using frequency and wavelength, then use this speed to find the time for sound to travel twice the thickness of the coating (to and back).
Step-by-step explanation:
The primary goal of this question is to calculate the time it would take for ultrasonic waves to travel through a nonstick coating that is 1.00 mm thick to ensure quality assurance. To determine this time, we utilize the formula for the speed of sound in a medium, which is v = f × λ, where 'λ' is the wavelength and 'f' is the frequency of the sound wave. In this context, 'v' represents the speed of the ultrasonic waves in the nonstick coating, and with a frequency of 25 kHz and a wavelength of 0.076 m, we can calculate 'v'.
The time 't' it takes for the sound to travel a given distance 'd' in the material is then calculated using the formula t = 2d/v, where the factor of 2 accounts for the sound traveling to the interface and back. Given that the thickness 'd' is 1.00 mm, which is equivalent to 1.00 × 10-3 meters, the time 't' can then be calculated. However, to determine the exact time the engineer should record for the correct thickness, one would have to use the calculated speed of the ultrasonic waves 'v' and solve for 't' using the thickness of the coating.