New Reply

Ohms law implies specific condition for the charge density

 
Share Thread Thread Tools
Aug10-12, 11:05 AM   #1
 

Ohms law implies specific condition for the charge density


We have all seen Ohms law, J=σE. This approximations makes sense in simple electric fields in which the charges are accelerated in parallel.

However as I will demonstrate, this implies a few conditions on the charge density (ρ) associated with the current density (J).

Now, from the continuity equation, ∂ρ/∂t=-DivJ
=-σDivE (using the approximation)
=-σ(ρ/ε) (From maxwells equations)
This is just a simple partial differential equation, solving...
ρ=A(x,y,z)exp(-σt/ε)+B(x,y,z)
This is a partial differential equation, so we have to allow the coefficients and constants as functions of position.

This implies that at time 0 (when the electric field is set up), the charge density is A+b, after some time the charge density reduces to B(x,y,z).
Has this been observed in ohmic resistors?

I find this result quite strange, is this a physical result?
PhysOrg.com
PhysOrg
physics news on PhysOrg.com

>> The better to see you with: Scientists build record-setting metamaterial flat lens
>> New analysis yields improvements in a classic 3D imaging technique
>> Research effort deep underground could sort out cosmic-scale mysteries
New Reply
Thread Tools


Similar Threads for: Ohms law implies specific condition for the charge density
Thread Forum Replies
VOLUME charge density from SURFACE/LINE charge density?? Classical Physics 9
Static charge density vs free charge density Advanced Physics Homework 1
Difference between charge, specific charge, relative charge and elimentary charge? High Energy, Nuclear, Particle Physics 1
current density constant in time implies charge density linear in time? Classical Physics 1
show that ((p implies q) and (q implies r)) implies (p implies r) is a tautology Calculus & Beyond Homework 2