In immersion testing in a small tank, a manually operated manipulator is used to:

• A. Both A and B
• B. Set the proper water path
• C. Set the proper transducer angle
• D. Set the proper index function

Answer: (A)

In immersion testing with a small tank, the hand-operated manipulator controls how the transducer sits in the water and how the beam is directed into the test piece. Two key things have to be set precisely: the water path, which ensures good acoustic coupling and the correct path length for the beam, and the transducer angle, which determines the incidence direction and whether you’re hitting the area of interest at the right angle. Without the proper water path and angle, you can get weak signals, poor coupling, or missed flaws.

So the essential idea is that the manipulator is used to adjust both the water path and the transducer angle, making the inspection geometry correct. The index function, while related to data collection, is not the primary role of this manual adjustment.