Which type of examination is characterized by its ability to test for defects without direct contact with the material?

The examination characterized by its ability to test for defects without direct contact with the material is remote visual examination. This method employs a camera or similar device to inspect a material or weld from a distance, allowing for the assessment of the material's integrity without needing to be physically in contact with it. Remote visual examination is particularly useful in situations where direct access to the surface is limited or where safety concerns could arise from getting too close to the area being inspected.

In contrast, liquid penetrant testing and magnetic particle testing both require contact with the material's surface to apply their respective media (penetrant or magnetic particles) to detect defects. ACFM (Alternating Current Field Measurement) is also a technique that involves interaction with the surface of the material, as it uses electromagnetic signals to detect surface and near-surface flaws. Thus, remote visual examination stands out for its non-contact approach while still providing crucial insights into the condition of materials.