MYP Physics: Electromagnetic Induction Explained

Electromagnetic induction is the process of generating an electric current or EMF by changing the magnetic field around a coil of wire — no battery involved. In MYP Physics you'll usually meet this by moving a magnet through a coil, or a coil through a field, and reading the voltage produced on a meter.

You won't be tested on Faraday's law by name or formula at MYP level, but you do need the idea behind it: a changing magnetic field through a coil induces an EMF, and a faster rate of change means a bigger induced voltage. That relationship gets its formal equation once you reach DP Physics.

Lenz's law states that an induced current always flows in a direction that opposes the change causing it. Push a magnet's north pole into a coil and the coil generates its own north pole to push back. It's conservation of energy at work — you have to do work to induce a current; nothing is free.

Electromagnetism describes how an electric current creates a magnetic field — the basis of electromagnets and electric motors. Electromagnetic induction is close to the reverse process: a changing magnetic field creates an electric current, which is how generators and dynamos work. Same relationship between electricity and magnetism, opposite direction of cause and effect.

A simple generator spins a coil of wire inside a fixed magnetic field, or spins a magnet inside a fixed coil. As the coil rotates, the magnetic flux passing through it keeps changing, which induces an alternating EMF — one that reverses direction every half-turn. That's why generators produce AC current, not DC.

Four things change the size of an induced EMF: how fast the magnet or coil moves, how strong the magnet is, how many turns are in the coil, and the coil's cross-sectional area. Increase any one of these and the induced voltage goes up — that's the pattern examiners expect you to describe and explain.

Electromagnetic induction mostly falls under MYP Sciences Criterion A (Knowing and Understanding), where you're asked to state, describe, explain or analyse how induced current or EMF is produced. It can also appear under Criterion B or C if your class runs a practical investigating what affects induced voltage, like coil turns or magnet speed.

Yes — if your school runs the IB's MYP eAssessment, electromagnetic induction can appear in the on-screen Sciences paper covering years 4 and 5 content, usually as a short-answer or extended-response question involving a diagram of a coil and magnet. Most schools, though, assess this topic through internal criterion-based coursework instead.

The biggest one I see marking mock papers: students state that a current is induced but never explain why — that it's caused by a changing magnetic field or flux, not simply a magnet being nearby. A stationary magnet next to a stationary coil induces nothing at all.

Start by being able to explain, in your own words, why motion or a changing field is essential — a static magnet next to a static coil produces zero induced current. Then work through practical scenarios: moving a magnet at different speeds, changing coil turns, and predicting what happens to the induced EMF each time.

MYP treats induction qualitatively — describing and explaining what happens without calculation. DP Physics, under the current guide with first exams in 2025, places electromagnetic induction in Topic D.4 (Fields), and it's HL-only content, using Faraday's and Lenz's laws to calculate induced EMF and current numerically.

It's abstract — your child can't see a magnetic field, only its effects, and that trips up learners who do best with things they can directly observe. In my years teaching this age group, the sticking point usually isn't the physics itself but linking cause (changing flux) to effect (induced current) in a written answer.

Ask your child to explain it out loud, in plain English, without notes — if they can describe why moving a magnet through a coil produces a current, they've genuinely understood it, not just memorised a diagram. Practising past criterion-based tasks under time pressure tends to help more than re-reading notes at this stage.