Explain, with reference to physics equations and principles, how the use of step-up and step-down transformers in high-voltage power lines reduces energy losses during the transmission of electrical power. Additionally, describe one design feature of either the transmission cables or the transformers themselves that further increases the overall efficiency of the system.
20 exam-style questions on Edexcel IGCSE Physics Electromagnetic induction. Each one has a worked solution and a mark scheme showing where the marks go.