Which phenomenon reduces the efficiency of electrical transmission over long distances?

The phenomenon that reduces the efficiency of electrical transmission over long distances is resistance. In electrical conductors, resistance causes power losses in the form of heat as current flows through the material. This is due to the collisions between the flowing electrons and the atoms in the conductor, which converts some of the electrical energy into thermal energy. The longer the distance that the electricity must travel, the greater the total resistance encountered, leading to more significant energy losses. This is why high-voltage transmission lines are used; by transmitting electricity at higher voltages, the current can be reduced, thereby minimizing the resistive losses, as they are proportional to the square of the current.

Understanding resistance is crucial not just in terms of efficiency but also when designing systems for long-distance electrical transmission, as it directly impacts the overall performance and costs associated with energy delivery.