AP Physics 2- Unit 12: Magnetism

For pole magnets,

ends at south, starts at north

Which symbol is into the page and which one is out of the page?

DOT - out

X- into

Magnetic fields details

unique, never cross, density/proximity is an indicator of strength

Is there such thing as a monopole?

NO : even if you SNAP a magnet, there will be a NS on the snapped magnets

What creates the magnetic field?

a current

RIGHT HAND RULE

Thumb- force

Pointer- qv

Middle- Magnetic field

qv VS. v depending on charge

+: qv and v are in the same direction

-:qv and v are in opposite directions

Right hand rule formulas

F = qv * B (dot products)

F=qvBsin(O)

B= uI/2pi®

Trajectory ANGLE=180/0

sin 180/0 results in 0 FORCE THEREFORE theres no force acting on the point, leading to the point going in a straight line/constant velocity

Trajectory ANGLE=90

sin(90) moves in a circular motion

What is the other, NOT ON THE TEST TRAJECTORY?

Helix, for any other angle aside from 90,180, and 0

Formula for the radius in a sin(90) or circular trajectory?

(WILL HAVE TO DERIVE ON THE TEST :,} )

Other force on a wire equation

Force two wires have on eachother (MUST BE ABLE TO DERIVE ON TEST)

What causes the different levels of magnetism? (dia,para,ferro)

unpaired electrons create difference

How do domains of another object affect magnetic field?

When domains line up to a magnetic field, they reinforce it by increasing it

Diamagnetism

Weakest,

Maganese

Para, despite electrons (a component of later physics)

Ferromagnet

can stay in a field even if removed

Spin → mini magnets

unpaired electrons

1-2 → para

LOTS → ferro

Induction - Flux

Measurement of magnetic field flow through some area

UNIT = Wb

Flux formula

Velocity Selectors info.

Choose a value for the speed cross field is perp. mag and electric field

How does the speed of the charge indicate the strength of the forces in the velocity selectors?

When flux changes…

induced EMF decreases

FORMULA FOR MOTIONAL EMF

e = Blv

with circular motion, use diameter

use the l perpendicuolar to v

FOR A SHIFT IN FLUX

pull OUT constants to address changes in B OR A OR COS(0)

motional emf

causes opposite movement magnetic breaking force

STEPS FOR LENZ’S LAW

1) B?

2) Is flux increasing or decreasing?

3a) If increasing, induced emf increase= induced I increase = induced B increase = reduced flux, therefore Bind is OPPOSITE OF Bext

3b) If decreasing, Bind is in same direction

Explain how to make electrogenerators are constructed and how it is able to generate electricity

INGREDIENTS

-coil + wire

-something to move it: (E.G. person water, air)

-magnet (stationary usually)
PART2: coil of wire changes angle from the magnet which changes the flux- makes a V difference (AKA: Electricity)

Are electro generators able to generate DC current

constant cycle generates AC, NOT DC!!!!!

DC - constant flow/non-fluctuating current