MDCAT Physics · Physics · Electromagnetic induction. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
A changing current in a coil changes the flux through the coil itself, so it induces an EMF that opposes the change. This is self-induction. A changing current in one coil can also induce an EMF in a coil nearby: mutual induction. An inductor carrying a current stores energy in its magnetic field.
In an AC generator a coil turns in a magnetic field and the induced EMF varies as a sine wave. It is greatest when the plane of the coil is parallel to the field, because the flux is then changing fastest.
A transformer uses mutual induction to change an alternating voltage. It does not work on steady DC, and it cannot give out more power than it takes in.
Thinking a step-up transformer steps up the current too. When the voltage goes up the current goes down by the same factor, because the power stays the same.
Answer: 440 V and 2.0 A
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