High-Voltage AC for Efficient Power Transmission

Steps:

• Power stations generate electricity, but transmitting it over long distances causes energy losses as heat in wires.
• To minimize losses, voltage is stepped up to very high levels using transformers, reducing current for the same power.
• Alternating current (AC) is used because it can be easily transformed to high voltages.
• At the destination, voltage is stepped down for safe use in towns.

Why B is correct:

• High voltage reduces current (from P = VI, so I = P/V), minimizing power loss (P_loss = I²R) over transmission lines.

Why the others are wrong:

• A: Low voltage causes high current and excessive I²R losses, inefficient for long distances.
• C: Direct current cannot be easily transformed to high voltages with simple transformers.
• D: Direct current is not typically used for main grid transmission due to transformation difficulties, despite high voltage.

Final answer: B