If you consider a current carrying conductor, every instant an electron enters the conductor, another electron will be leaving the conductor. Thus, the current carrying conductor will not be charged (i.e. it would not have any net positive or negative charge). Remember a dipole has zero net charge, but it does have electric field around it (although the net electric field around a dipole drops to insignificance as the distance increases to multiples of the dipole separation). So, if net charge is zero, it doesn't mean there is no electric field, only that it is small (i.e. largely cancelled because every electron in the conductor is paired as a dipole), and gets rapidly smaller with distance.
It is important to notice that, if we assume only electrons to be moving, and kernels (positive nuclei) to be static, the magnetic field will be produced only due to electrons.
The speed at which energy or signals travel down a conductor is actually the speed of the electromagnetic wave, not the movement of electrons (this is an modified statement extracted from wiki encyclopedia-speed of electricity).
Does it mean that an electric field and magnetic field exist around the current carrying conductor?
Does it mean that only a magnetic field exists around the current carrying conductor?
By the discussion until now (2/11/2013), I have found a difference in answers with respect to AC and DC. Can everyone update their answers with respect to both the cases (AC and DC)?
- Relativistic electromagnetism-Wiki provides you an idea about fields around a current carrying conductor, with respect to different frame of reference.
- I went through quite similar question Does a current carrying wire produce electric field outside? . I found the first answer was assuming electric field to be existing around the current carrying conductor, and the second answer was assuming electric field to be not existing around current carrying conductor.
- I went through the link: propagationtime.pdf, it expresses the presence of both electric and magnetic fields around a current carrying conductor.
- I took a look on this question, [Confusion between Electric field and Magnetic field of a charged particle].(Do moving charged particles have both magnetic and electric fields?), it makes a clear attempt to say that, there is no electric field around a current carrying conductor.