Final answer:
Transformers enable high-voltage transmission from power plants, reducing energy loss, and convert the voltage to safer levels for residential use.
Step-by-step explanation:
Transformers are especially useful in the transmission of electricity from power plants to residences because they allow for the transmission of electric power at very high voltages, which reduces resistive heating losses in the lines. This is crucial since high-voltage transmission requires less current, leading to lower energy losses. Once the power reaches residential areas, transformers then step down the high voltage to the lower voltages suitable for household use, typically between 110 to 220 volts, ensuring safety and practical utility for electrical appliances.