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What you will learn in Magnetism & Electromagnetism

1. Magnetic Fields
Field lines that close on themselves, because there is no such thing as a lone magnetic pole.
2. Force on a Moving Charge
A force always at right angles to the motion turns a particle in a circle without ever changing its speed.
3. Force on a Current
The same force, acting on charges that cannot leave the wire — so the wire itself is pushed.
4. Electromagnets in Depth
The full treatment the circuits module's preview was building towards — geometry, cores, and what a coil can actually lift.
5. Electromagnetic Induction
Move a magnet near a coil and current flows with no battery anywhere. It is the change that matters, not the strength.
6. Lenz's Law
The induced current always opposes the change that made it — which is conservation of energy, wearing a disguise.
7. Generators and Motors
One machine, run in two directions — and one number that describes both.
8. Maxwell's Unification
Four equations, and a speed nobody was looking for.
9. Self and Mutual Inductance
A coil opposes changes in its own current — which is why switches spark — and drives an EMF in any coil its flux threads, which is how a transformer works.
10. Displacement Current
No charge crosses a capacitor's gap, yet Ampère's law needs a current there. Maxwell's changing electric field supplies exactly the right amount.
11. Biot–Savart and Ampère's Circuital Law
Two ways to get a field from a current: add up every piece of wire's contribution, or walk round a closed path and count the current inside. Both land on the formulas this module has been quoting.
12. The Moving-Coil Galvanometer
The loop torque turned into a meter: a radial field makes the scale linear, a shunt makes it an ammeter, a series resistor a voltmeter — and every real meter changes the circuit it measures.
13. Earth's Magnetism
Three numbers describe the field wherever you stand — declination, dip and the horizontal component — and a tilted bar magnet gets them only roughly right.
14. Magnetic Materials
One number, the susceptibility, sorts every material into dia-, para- and ferromagnets — and iron, which remembers, needs a loop instead of a number.

What you will learn in Magnetism & Electromagnetism

1. Magnetic Fields

Field lines that close on themselves, because there is no such thing as a lone magnetic pole.

2. Force on a Moving Charge

A force always at right angles to the motion turns a particle in a circle without ever changing its speed.

3. Force on a Current

The same force, acting on charges that cannot leave the wire — so the wire itself is pushed.

4. Electromagnets in Depth

The full treatment the circuits module's preview was building towards — geometry, cores, and what a coil can actually lift.

5. Electromagnetic Induction

Move a magnet near a coil and current flows with no battery anywhere. It is the change that matters, not the strength.

6. Lenz's Law

The induced current always opposes the change that made it — which is conservation of energy, wearing a disguise.

7. Generators and Motors

One machine, run in two directions — and one number that describes both.

8. Maxwell's Unification

Four equations, and a speed nobody was looking for.

9. Self and Mutual Inductance

A coil opposes changes in its own current — which is why switches spark — and drives an EMF in any coil its flux threads, which is how a transformer works.

10. Displacement Current

No charge crosses a capacitor's gap, yet Ampère's law needs a current there. Maxwell's changing electric field supplies exactly the right amount.

11. Biot–Savart and Ampère's Circuital Law

Two ways to get a field from a current: add up every piece of wire's contribution, or walk round a closed path and count the current inside. Both land on the formulas this module has been quoting.

12. The Moving-Coil Galvanometer

The loop torque turned into a meter: a radial field makes the scale linear, a shunt makes it an ammeter, a series resistor a voltmeter — and every real meter changes the circuit it measures.

13. Earth's Magnetism

Three numbers describe the field wherever you stand — declination, dip and the horizontal component — and a tilted bar magnet gets them only roughly right.

14. Magnetic Materials

One number, the susceptibility, sorts every material into dia-, para- and ferromagnets — and iron, which remembers, needs a loop instead of a number.