griffiths 5 22 - physics & astronomyhomepage.physics.uiowa.edu/~rmerlino/129fall12/griffiths...
TRANSCRIPT
Griffiths 5.22 (Magnetic vector potential for a finite wire)
2
1
2 22 2
2 2 2 21 1
1 2 1 22 2 2 22 1
2 2 2 22 2 1 1
1 22 2 2 22 2 2
2 2 2 22 2 2 2
ˆ ˆ( ) ln4 4 4
ˆ ˆ4
4
z
o o o
z
oz
o
z s zI I Idl dzA r z z
s z z s z
s s z s s zIAB A
s z s z z s z
s s z z s zIB
z s z z s z
r
1 22 2 2 21 1 1
2 2 2 21 1 1 1
2 1
2 2 2 22 1
ˆ
ˆ4
o
s s z z s z
z s z z s z
I z zB
s s z s z
2 1 ˆsin sin
4o IBs
zdl
s r
z
z1 z2
dA r = s2 + z2
s
z1 z2