Py 212 Test 3

Front 1

Φ_B
magnetic flux

Back 1

Φ_B = |B|*A*cos(θ)

Φ_B (closed surface) = 0

Front 2

Magnetic Field Lines
-Out / In
-Monopoles
-Strength

Back 2

Out of North pole
Into South pole
NO monopoles (make closed loops)
Closer Lines = stronger field

Front 3

Magnetic Field Facts:
(1) Sources and (2) Forces

Back 3

Sources: produced by moving charges
Forces: only "felt" by moving charges

Front 4

MFL Symbolism

Back 4

. == out of page (point of arrow)
x == into page (tail of arrow)

Front 5

Force on moving charge
|F| = q*|E|
applied to magnetic fields

Back 5

|F| = q*|v|*|B|*sin(θ)

Front 6

Right Hand Rule
F is ┴ to B and V

Back 6

1) Finger in direction of V
2) Curl fingers in direction of B
3) Thumb points direction of F
-Neg charge, opposite thumb

Front 7

Units of Magnetic Field

Back 7

(Ns / Cm) = Tesla, "T"

Gauss = 10^-4 T

Front 8

Charge Moving in circular path
Derive from: |a_c| = (v^2)/r
Constant B

Back 8

|F| = (m*v^2)/r
qvB = (m*v^2)/r
qB = (m*v)/r

Front 9

Mass spectrometer

Back 9

Fire particles in field
-determine reaction --> mass
-larger mass, larger radius

Front 10

"Singly Ionized" particles

Back 10

q = 1*e

where e = 1.6 x 10^-19

Front 11

Velocity of charged particle
in a field (parallel plates)

Back 11

Find where |F_E| = |F_B|

v = |E| / |B|

Front 12

Force on current

Back 12

|F| = I*l*B*sin(θ)

Front 13

Right Hand Rule v1.1
F is ┴ to B and I

Back 13

1) Finger in direction of I
2) Curl fingers in direction of B
3) Thumb points direction of F
-Neg charge, opposite thumb

Front 14

Torque on a circuit loop
recall: τ = F*r*sin(θ)

Back 14

τ = I*A*B*sin(θ)
1 loop = I current
n loops = n(I) current

Front 15

μ - magnetic moment vector
condensed τ equation

Back 15

μ == NIA
τ = (NIA)*B*sin(θ)
τ = μ*B*sin(θ)

Front 16

Straight and Curly rule
RHR for current
Finding torque direction

Back 16

1) Curl fingers in direction of current
2) Thumb points in direction of torque

Front 17

Magnitude of B
Given current, radius

Back 17

|B| = (μ_0)*I / 2π*r

Front 18

Constant μ_0

Back 18

Permeability of free space

μ_0 = 4πe-7 Tm/A
exact --> definition

Front 19

Straight and Curly v1.1
Finding MFL direction

Back 19

1) Point thumb straight (w/current)
2) Curl fingers to show direction of MFL's

Front 20

Magnitude of Force
Given length of wire
Given separation

Back 20

|F| = (μ_0)*I*I2*l / 2π*d

l= length of wire
d = separation distance

Front 21

Direction rule
Force on current

Back 21

1) Point fingers toward current
2) Curl in direction of B
3) Thumb points direction of force