What type of welding uses an electric arc to join metals?

The correct choice refers to Arc Welding, which is a broad categories of welding processes that utilizes an electric arc to create heat needed for melting and joining metals. In this process, an electric current is passed through the electrode and the base metals, creating a high-temperature arc. This heat is sufficient to melt the materials at the joint, allowing them to fuse together upon cooling.

Arc Welding encompasses various types of welding techniques, including both TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding, which are specific processes that fall under the arc welding umbrella. While both TIG and MIG welding also utilize an electric arc, they employ different methods for feeding the filler material and shielding gas. Spot Welding, on the other hand, uses electrode tips to apply pressure and current at specific points; it is not classified under arc welding as it does not involve a continuous electrical arc across a gap.