Dear Fellows I have just came across with the basics of electromagnetism, and about the application of electric and magnetic force on charge particle,(adsbygoogle = window.adsbygoogle || []).push({});

Ohm's law for charge is

j=σE (1)

if the charge is moving with the speed "u"

then, j=σ(E+u[itex]\times[/itex] B) (2)

force on a charge by electric field is

F=q.E (3)

if the charge is moving through the electromagnetic field,

F=q(E+u[itex]\times[/itex]B) (4)

I am supposed to use equation of motion for solid particles i.e.,

σ_ij,j+f_i=ρu'_i (u'=acceleration ' is for time derivative) (5)

my questions are

1- How equation (1) is converted to equation (2) if the partical started moving ??

2- similarly how equation (3) is converted to equation (4)

3- in final form eq (5) if found f_i = lorantz force but in (5) they use f_i =J[itex]\times[/itex]B, why they did not use equation (4) in this situation.

thank you for your cooperation

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# Ohm's Law for moving charge

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