A 45 degree shear angle beam transducer produces a wave in the metal that is polarized:

• A. Perpendicular to the direction of propagation and at 45 degrees to the entry surface
• B. Perpendicular to the entry surface
• C. In the direction of propagation and at 45 degrees to normal to the entry surface
• D. Perpendicular to the direction of propagation and parallel to the entry surface

Answer: (A)

In a shear-angle beam, the wave produced in the metal is a shear (transverse) wave, so its particle motion is perpendicular to the direction the wave is traveling. If the transducer is oriented to send the wave at a 45° angle to the entry surface, the ray path is 45° relative to the surface. The polarization direction is perpendicular to that ray, which ends up being 45° to the entry surface as well. So the wave is polarized perpendicular to its propagation direction and at 45° to the entry surface, which matches the described option.