IGCSE Physics / Electric motors and electromagnetic induction
Transmitting electricity: why the voltage is stepped up
Edexcel International GCSE Physics (4PH1), chapter 21: Electric motors and electromagnetic induction, specification point 6.18P. Part of the full course.
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Electricity is transmitted through the grid at a very high voltage so the current is low and less energy is wasted heating the cables. Transformers then reduce the voltage to a safe value before electricity reaches homes.