Question

Of the following, which is most appropriate to determine the needs to qualify and certify personnel whose only NDT function is to operate digital thickness equipment.

Answer 1

To determine the appropriate time for the ultrasonic transducer to reflect waves off the correct coating thickness, the speed of sound in the coating is calculated, and the time is derived using the travel distance and speed of sound.

Step-by-step explanation:

To determine the apropriate time recorded for a coating thickness of 1.00 mm using an ultrasonic transducer, we can use the formula for the wave speed (v):

v = f × λ

Where:

f = frequency of the ultrasonic waves (25 kHz).

λ = wavelength of the ultrasonic waves in the coating (0.076 m).

First, calculate the speed of the ultrasonic waves:

v = 25,000 Hz × 0.076 m = 1900 m/s

Since the thickness (d) of the coating is 1.00 mm, or 0.001 m, and the waves travel back and forth, we need to double the distance:

Total distance = 2 × d = 2 × 0.001 m = 0.002 m

The time (t) taken for the waves to travel this distance can be found using the formula:

t = total distance/v

Plug in the known values:

t = 0.002 m / 1900 m/s = 0.00105 s or 1.05 μs

Therefore, the time recorded if the coating is the correct thickness should be 1.05 μs.