Most electricity comes in the form of ___.

• A. DC
• B. Both AC and DC
• C. None of the above
• D. AC

Answer: (D)

Electric power systems rely on alternating current because it can be easily transformed to different voltages. Power plants generate AC, and transformers make it practical to raise voltage for long-distance transmission (reducing losses) and then lower it for safe use in homes. While direct current is used in some applications—like batteries and many electronics—most electricity delivered to consumers and across the grid is AC. So, most electricity comes in the form of alternating current.