ANS:B - Rockwell

Measurement of the area of the indented surface is not involved in the Rockwell hardness testing method. Explanation:

1. Rockwell Hardness Testing: In Rockwell hardness testing, an indenter is pressed into the surface of the material under a predetermined load. The depth of penetration of the indenter into the material is measured, typically using a depth-measuring system in the testing apparatus. The hardness value is then determined based on the depth of the indentation, which is indicated on a scale. There are different scales within the Rockwell hardness testing method, such as the Rockwell C scale for harder materials like steel and the Rockwell B scale for softer materials like aluminum.
2. Area Measurement: Unlike methods such as Vickers, Knoop, and Brinell, the Rockwell hardness testing method does not involve the measurement of the area of the indented surface. Instead, it relies solely on measuring the depth of penetration of the indenter. This makes Rockwell hardness testing relatively simpler and quicker compared to methods that require area measurements.