What is the maximum angle that the radiation can be shot on?

• A. 12.5 deg
• B. 15 deg
• C. 26.5 deg
• D. 44 deg

Answer: (C)

The maximum angle for directing radiation is set by geometry to keep the weld fully within the radiographic view and to limit distortion. As the beam angle grows from normal, features can become foreshortened and parts of the weld may move out of the field of view, degrading visibility of important details like the root. In this problem, the geometry translates to a ratio that yields theta_max = arctan(0.5), which is 26.5 degrees. Exceeding this angle would push part of the weld outside the usable radiographic area and worsen image quality, while smaller angles wouldn’t adequately illuminate or reveal the weld features. Therefore, 26.5 degrees is the correct maximum.