- The loss of energy due to heating up of energy is :
*H = I*, where^{2}Rt- I is current in wire,
- R is resistance of wire
- and t is time of current flow

- Thus power loss is
*P = I*^{2}R - Power loss can be reduced by reducing current or resistance.
- Since , over long distance, due to extremely high values of
*l*, the total resistance of the wire becomes very high and is hard to reduce. - We can reduce power loss by reducing current.
- We use the Step-Up transformers to increase the voltage many times using Ns>Np.
- , so Vs>Vp

- , So when Ns>Np , the current Is < Ip
- Thus with higher voltage being transmitted , the current is reduced
- Thus power loss is also reduced.
- Then a step-down transformer is used near households to reduce the voltage to usable amounts.

Extract from *Physics Stage 6 Syllabus © 2017 *NSW Education Standards Authority (NESA)