Final answer:
Face shields are worn during arc welding to provide protection to the welder's face and eyes from the intense heat, sparks, and high-energy electromagnetic radiation produced during the process.
Step-by-step explanation:
Face shields are worn during arc welding to protect the welder's face and eyes from the hazards associated with the process.
When arc welding, a high-energy electric arc is created that emits intense heat, sparks, and high-energy electromagnetic radiation. The face shield acts as a barrier to prevent the welder's face from being burned by the extreme temperatures and prevent their eyes from being exposed to the dangerous radiation.
This is similar to how lead aprons and shielding are used in medical imaging to protect patients and technicians from radiation exposure.