12.3 Transmission of electrical power

12.3.1    Outline the reasons for power losses in transmission lines and real transformers.

- Power losses in transmission lines and real transformers occur because energy is dissipated when they warm up, since they have a resistance. Having a thick wire can decrease the resistance occurred.
- Flux losses are caused by magnetic leakage. a transformer is only 100% efficient if all of the magnetic flux that is produced by the primary links with the secondary

12.3.2    Explain the use of high-voltage step-up and step-down transformers in the transmission of electrical power.

According to the formula P=I^2R, the power lost in wires is dependent on the current. Step-up transformers can therefore be used to lower the current without having to loose any power as well as minimizing dissipation. The high voltage created however is too dangerous to be use at home thus, the voltage is at the end stepped down so that it can be use safely by consumers.

12.3.4    Suggest how extra-low-frequency electromagnetic fields, such as those created by electrical appliances and power lines, induce currents within a human body.

Photons sent out from electromagnetic fields are too low to ionize anything. However it can still induce currents in the human body.

12.3.5    Discuss some of the possible risks involved in living and working near high-voltage power line

• statistical evidence revealed that there are higher risks of getting leukemia or cancer when living near power lines.
• changing extra-low-frequency electromagnetic fields are theoretically able to induce currents within any conductor, including human bodies nearby
• current experimental evidence suggests that low-frequency fields do not preferentially harm genetic material
• risks are likely to be dependent on current, A.C frequency and length of exposure