(nm02) Magnetic Field 磁場 (I)


News

  1. Marks to date: See Web
  2. MS--Electrostatics Applied (A Drawing Fields & Potentials -- Complete Handout by Friday if you have not passed part A) See ne09

Review: Right Hand Rules

From electric to magnetic fields

ElectricMagnetic
NO
For both, closeness of lines indicate strength of the field.
From +ve → -ve Complete circle -- outside: N→S inside: S→N
Draw Equipotential Lines???????????

Key Points

Fields: Electric & Magnetic
Point $$ \mathbf { \vec E }_{point} = {1 \over {4 \pi \epsilon_o}} \, \color{fuchsia} {q \over r^2} \, \mathbf {\hat r } $$ $$ \mathbf { \vec B }_{point} = {\mu_o \over {4 \pi}} \, \color{fuchsia} {q \over r^2} \, \mathbf {\color{fuchsia} {\vec v}} \times \mathbf {\hat r } $$

Moment $$ \mathbf {\vec p} = q \, \mathbf {\vec s} $$ $$ \mathbf {\vec \mu} = I \, \mathbf {\vec A} $$
Dipoles (Farfield) $$ \mathbf{ \vec E}_{on \,axis} = {1 \over {4 \pi \epsilon_o}} \, \color{fuchsia} {2 \mathbf {\vec p} \over z^3} \mathbf {\hat z} $$ $$ \mathbf{ \vec B}_{on \,axis} = {\mu_o \over {4 \pi}} \, \color{fuchsia} {2 \mathbf {\vec \mu} \over z^3} \mathbf {\hat z}$$

$$ \lambda \, [C m^{-1}] $$ $$ I \, [C s^{-1} = A] $$
$$ \mathbf {\vec E}_{line,\infty} = {1 \over {4 \pi \epsilon_o}} \, \color{fuchsia}{2 \lambda \over r} \, { \mathbf {\hat r }} $$ $$ \mathbf {\vec B}_{wire,\infty} = {\mu_o \over {4 \pi}} \, \color{fuchsia}{2 I \over r} \, { \mathbf {\hat \theta }} $$

Gauss & Ampere $$ \iint \mathbf {\vec E} \, \cdot d \mathbf {\vec A} = {Q \over \epsilon} $$ $$ \oint \mathbf {\vec B} \, \cdot \, d \, \mathbf {\vec s} = {\mu_o I} $$

Lorentz$$ \mathbf a = { m_g \over m_e} \mathbf {\vec G} + { q \over m_e} \mathbf {\vec E} + { q \over m_e} \mathbf {\vec v} \times \mathbf {\vec B} $$

Lecture Power Points

Knight vs4 chapter 29 Knight vs3 chapter 32 (to Slide 44)

Further Study...

  1. Magnet making Current Explain result in pictures like writing scientific paper
  2. Electric and Magnetic Forces don't exist: It is Electro-Magnetic Force
  3. What forces are real? (break time)

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