Why are step-up transformers crucial in power transmission?

Step-up transformers are crucial in power transmission because they increase voltage while decreasing current, reducing energy loss during transmission.

In more detail, the primary function of a step-up transformer in power transmission is to increase the voltage level from the power station before it is transmitted over long distances. This is achieved by having more turns on the secondary coil than on the primary coil. The increase in voltage is directly proportional to the ratio of the number of turns in the secondary coil to the primary coil.

The reason for increasing the voltage is to decrease the current. According to Ohm's law, the current in a circuit is inversely proportional to the voltage. Therefore, by increasing the voltage, the current is reduced. This is significant because the power loss in transmission lines is directly proportional to the square of the current, according to Joule's law. Hence, by reducing the current, the power loss due to heat dissipation in the transmission lines is significantly reduced. This makes the transmission of electricity over long distances more efficient.

Furthermore, the use of high voltage for power transmission also reduces the size and weight of the conductors needed, making the infrastructure more cost-effective. The reduced current also means less heat is produced, which extends the lifespan of the transmission lines and reduces maintenance costs.

IB Physics Tutor Summary: Step-up transformers are key in power transmission as they boost voltage and lower current, cutting energy loss over long distances. They work by having more turns in the secondary coil, which increases voltage, thus reducing current. This reduction in current decreases power loss and makes the system more efficient, cheaper to maintain, and extends the life of transmission lines.