(b) the magnetic susceptibility of the paramagnetic if the maximum attraction force equals F niox = 160 [tN.
3.287. A small ball of volume V made of paramagnetic with susceptibility x was slowly displaced along the axis of a current-carrying
coil from the point where the magnetic induction equals B out to the
region where the magnetic field is practically absent. What amount
of work was performed during this process?
3.6. ELECTROMAGNETIC INDUCTION.
MAXWELL'S EQUATIONS
• Faraday's law of electromagnetic induction:
del3
(3.6a)
• In the case of a solenoid and doughnut coil:
(1) = NO1,
(3.6b)
where N is the number of turns, cl3.1 is the magnetic flux through each turn.
• Inductance of a solenoid:
L =-- iutto 71217.
(3.6c)
• Intrinsic energy of a current and interaction energy of two currents:
L/ 2
W=—r. 7
W12== L121112.
• Volume density of magnetic field energy:
B2
= 2ulto
2
• Displacement current density:
013
jclis= at
• Maxwell's equations in differential form:
as
'
v x
V • B=0,
at
aD
V x H=1-4 -
- '
V•D=p,
where V X
rot (the rotor) and V. ---- div (the divergence).
• Field transformation formulas for transition from a reference frame K
to a reference frame K' moving with the velocity vo relative to it.
In the case 170 << c
E' = E
B' = B — [vo Elic2
(3.6h)
In the general case
E' 11 =E ll '
B
E14-[voll]
B' =
°
B —Iv El/c2
0. —(v0/02 '
yi-0,0/02
where the symbols II and I denote the field components, respectively parallel
and perpendicular to the vector vo.
(3.6d)
(3.6e)
(3.6f)
(3.6g)
(3.6i)
10*