(b) the magnetic susceptibility of the paramagnetic if the maxim-
um attraction force equals F niox = 160 [tN.
3.287. A small ball of volume V made of paramagnetic with sus-
ceptibility 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) = NO 1 , (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== L12 111 2. - Volume density of magnetic field energy:
B 2
=2ulto 2 - Displacement current density:
013
jclis= at - Maxwell's equations in differential form:
as
v x (^) at ' V • B=0,
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 17 0 << c
E' = E B' = B — [vo Elic 2 (3.6h)
In the general case
E' 11 =E (^) ll ' B
E14-[voll] B' = B —Iv El/c° 2
- —(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*