Question

What is the physical reason that using alternating current makes it much easier to boost electricity up to a high voltage for long trips and back down for safe home use?

Accepted Answer

To move electricity over long wires, we need very high voltage, which is the pressure that pushes electricity along. Pushing electricity at high pressure saves energy by stopping it from turning into heat inside the wire. To change this pressure, we use a device called a transformer. A transformer has two coils of wire sitting side-by-side but not touching. When electricity flows through the first coil, it creates a magnetic field. Because alternating current is always switching directions, this magnetic field is always expanding and shrinking. This constant movement of the magnetic field pushes electricity into the second coil. This process, called electromagnetic induction, only works when the magnetic field is moving. Direct current, which flows in only one steady direction, creates a still magnetic field that does not move, so it cannot push power into the second coil. Think of it like waving a magnet near a wire; the wire only gets a jolt of power while the magnet is in motion, not while it is standing still. By using alternating current, we can easily use transformers to crank the pressure way up for the trip and then back down for your house.

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What is the physical reason that using alternating current makes it much easier to boost electricity up to a high voltage for long trips and back down for safe home use?

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