CBSE · Class 12 · Physics · Alternating CurrentWhy is alternating current (AC) preferred over direct current (DC) for long-distance transmission of electric power?

Alternating current (AC) is preferred over direct current (DC) for long-distance transmission primarily because AC voltage can be easily stepped up or stepped down using transformers. By stepping up the voltage to very high levels at generating stations, the current in transmission cables is significantly reduced ($P = VI$). Since transmission line power loss due to heating depends on current ($P_{loss} = I^2R$), stepping up voltage drastically minimizes energy loss during long-distance transmission, making the system highly efficient and cost-effective.