1. Magnetism and ElectroMagnetism

2. Magnetism in Technology

3. Quick Definitions One charge Two Charges There is no “magnetic charge”
Monopole
Two Charges
Dipole
There is no “magnetic charge”
“magnetic monopole”

4. Vector Products Dot Product Cross Product Vector x Vector = Scalar
Vector x Vector = Vector
Right-hand rule
Non-Commutative

5. Quantum Origins
While there is no magnetic charge that makes a particle “north” or “south”, every particle does have a magnetic dipole (north-south pair)
Magnetic dipole called “spin”
Note: nothing is actually ‘spinning’
‘Spin’ is a fundamental property of matter

6. Types of Magnets Ferromagnetic Paramagnetic Diamagnetic
Magnetic moments of unpaired electrons aligned in one direction
Paramagnetic
Random alignment due to thermal fluxuations
Diamagnetic
Align to counter an external magnetic field

7. Periodic Table

8. Ferromagnetism
“Permanent Magnets” are a result of the energy structure of the incomplete 3d shell in some materials
Unpaired spin in 3d shells with protective 4s orbitals

9. ElectroMagnetism Spin is one source of magnetism
Moving charges also create a magnetic field that rotates around the axis of motion + +
Electric Field
Magnetic Field

10. 3D Vector Convention
Consider the field in and out of the page being shown with arrows (like bow-and-arrows)
Coming toward you
(Out of the page)
Going away from you
(Into of the page)

11. Fun Fact: Relativity
Because magnetic fields are created by a moving charge, and movement is relative to your reference frame, magnetism is a result of relativity.
This is why Einstein’s work in electrodynamics lead him to develop the Theory of Special Relativity

12. Electrodynamics
If we consider a number of charges, we end up with a resultant magnetic field that looks like this
Right Hand Rule:
Thumb: Current
Fingers: B-Field

13. Solenoids: Wire Coils
Applying this rule, we can figure out what the magnetic field around a coil looks like.

14. Solenoids
We can create a region of an aligned magnetic field.

15. Moving Charge in a B-Field
Units of B-field: Tesla

16. Practice Problems
Section Review
Page 767, Questions 1-3

19. Deflection of a moving charge in a B-Field
Length Contraction
An object traveling relative to an observer will be shorter in the observers frame
Time Dilation
A clock travelling relative to an observer will measure time passing more slowly than in the observers frame.