Magnetism
History of magnetism
the earth behaves as a magnet
the poles of earth
diagram of geographic north and magnetic north
(pierre Maricourt) lodestones= when rocks suspended the 2 points aligned with earths N-S axis (leading stones)
(who was first) william gilbert compared the orientation of a magnetized needle on a piece of lodestone with a compass at various locations on earth.
compared lodestone orientation with N-S orientation => action at a distance- no visible contact but they move
lodestones= magnetic stones with their domains aligned
Current in a Magnetic field
B= the magnetic field I= the amount of current in the wire (A) l= the length of the wire in the magnetic field (m)eters
Fm=BIL
philosophers
J.J. Thompson
determined the charge to mass ratio of the electron
found that electrons have q/m ratios of x10^11 c/kg
Daltons Atomic Theory
(Billiard Ball Model) 1. all matter is made up of tiny particles (sold sphere) 2. Atoms are indestructable and inchangable 3. when elements react, their atoms combine in simple, whole number ratios
Faraday and Lenz
ellectrically powered
(electric generator) input= kinetic output= electrical
water dam= work.... gives you electricity
(electric motor) input= electrical output= kinetic
electricity gives you.... power to work (car)
Lenz' law= when moving a magnet in a solenoid the forces b/w the magnet and induced magnet causes work/energy current
(induced magnetism) diagrams from notes
Hanz Oerstad= proved that electric current caused magnetic fields.
faraday= moving a magnet in a coil of wire or any conductor tube makes CURRENT
Mass Spectrometer
to ways to give particle speed: -^Eelectric = ^Ekinetic qV=1/2mv^2 or V=E/B
Fmagnetic= Fcentripetal v=qBr/m
(what does it do) gives you the chemical make up of a compound
PIECES
vaporization-ionization chamber-acceleration plates/velocity selection chamber-curving chamber-counter/detector
velocity selector= speeds up particles
balance Fe=Fm qE= qvB velocity
(voltage) W=^E q^V= 1/2mv^2
need to calc how fast the ions are!
forces and fields
Magmetic Force Fm= qvB velocity is perpendicular to the magnetic field
if you wanna suspend a wire b/w magnets.... Fg=Fm mg=BIL and use hand rules
motor effect force
the deflecting force acting on a charged particle moving in a B
Fm=Fe when you have a charged object that goes through undeflected
V=E/B finding speed of electron
venn diagram of electric and magnetic fields
Domain Theory (save the cowboys)
mini magnets inside a bar. rubbing it with a magnet lines them up. (belt buckles are attracted to the hull of ships)
however when they have random domains that means they are no longer magnetized. dropping it will unalign the domains
diagram of bar magnet out of N into S
Hand Rules
solenoid
same hand rules for e- thumb is the indicator of north and the fingers=field
increase amount of wire= increase force of field
with a magnet
force is always PERPENDICULAR to both the magnetic field and the direction of charge flow
speed stays the same, force is perpendicular to direction of flow therefore no work
the PALM shows the direction of the magnetic force (causes the deflection)
still use left hand for electrons and thumb goes in direction of charge flow
fingers in direction of magnetic field=N to S
on a wire
X=into the page (arrow feathers)
O= out of the page (arrow coming at your face)
do these wires attract ot repel?
electrons=left hand
protons=right hand
conventional current
thumb indicates direction of the charge flow
fingers curl in direction of the magnetic force
