Electric Charge and Magnetism: Constant or Varying Magnetic Field?

[Dikshant]

If an electric charge is moving with constant velocity,what does it create?? A constant magnetic field or 1 which is varying with time?? What if it accelerate?

 

[Vagn]

If an electric charge is moving with constant velocity,what does it create?? A constant magnetic field or 1 which is varying with time?? What if it accelerate?

Does a wire with a constant current through it create a magnetic field?

 

[Dikshant]

Does a wire with a constant current through it create a magnetic field?

Thanks for reply,but m already a bit confused and that's a different case.

 

[Dikshant]

Does a wire with a constant current through it create a magnetic field?

Yeah,a constant magnetic field

 

[ChrisVer]

yes it generates a constant in time magnetic field following the Biot Servart law
http://maxwell.ucdavis.edu/~electro/magnetic_field/pointcharge.html

If it is accelerated it is going to generate radiation (time varying magnetic field)

 

[Dikshant]

yes it generates a constant in time magnetic field following the Biot Servart law
http://maxwell.ucdavis.edu/~electro/magnetic_field/pointcharge.html

If it is accelerated it is going to generate radiation (time varying magnetic field)

And

yes it generates a constant in time magnetic field following the Biot Servart law
http://maxwell.ucdavis.edu/~electro/magnetic_field/pointcharge.html

If it is accelerated it is going to generate radiation (time varying magnetic field)

And what happens when a varying electric field is working in an area??

yes it generates a constant in time magnetic field following the Biot Servart law
http://maxwell.ucdavis.edu/~electro/magnetic_field/pointcharge.html

If it is accelerated it is going to generate radiation (time varying magnetic field)[/QAnd

 

[Dale]

If an electric charge is moving with constant velocity,what does it create?? A constant magnetic field or 1 which is varying with time?? What if it accelerate?

The fields from a moving charge are given by the Lienard Wiechert potentials

http://en.wikipedia.org/wiki/Liénar...onding_values_of_electric_and_magnetic_fields

It doesn't have an explicit time dependence, but the input variables are functions of time so the result is also.

 

[Dale]

yes it generates a constant in time magnetic field following the Biot Servart law
http://maxwell.ucdavis.edu/~electro/magnetic_field/pointcharge.htmld

You are misinterpreting this. There is no explicit time dependence, but r is a function of time. So the field is not constant in time.

 

[ChrisVer]

Yes you are right DaleSpam...
Indeed, I misinterpreted this...I also thought about that when I saw the r in the equation, but then... I got confused with the u=const case not generating electromagnetic radiation... but the EM radiation is something different (has to do with the Poynting vector as well)...

 

[Dale]

Yes that is correct. The fields generated by the Biot Savart law or the Lienard Wiechert potential for constant velocity do not generate "radiation". The fields stay localized to the charge. They change over time, as the charge moves, but their relationship to the charge doesn't change.

 

[Dikshant]

Thank you all