Final answer:
Increasing the arc length in welding processes such as FCAW, GMAW, and SAW increases the arc voltage drop across the arc due to higher resistance in the air.
Step-by-step explanation:
The impact of an increase in arc length for the FCAW (Flux-Cored Arc Welding), GMAW (Gas Metal Arc Welding), and SAW (Submerged Arc Welding) processes is that it increases the arc voltage drop across the arc. This is because as the arc length increases, the resistance of the air the arc passes through also increases, which requires a higher voltage to maintain the arc. Contrary to the options provided in the question, it is important to note that the arc voltage is indeed affected by changes in the arc length and the amperage could also be affected depending on the overall setup and parameters of the welding process. However, the question focuses on the changes in the arc voltage drop, which increases with an increase in arc length.