Cause of Rlectromagnetic Radiation From a Current Carrying Conductor

Dear Tony,

I tried in google already, but i didn't get the answer for my quetion.

Have a look for

Ohm's Law (volt drop)

Fleming's rules (magnetic flux)

Electrostatic & Corona effects (potential around a conductor)

My question is simple, whether differential voltage drop along the conductor causes electric field or not.

I think your understanding is essentially correct. The summation of all the infinitesimally small voltage drops gives the total electric field.

Following is a quote from the Wikipedia article on electric fields. (See also the article on magnetic fields).

• According to equation (1) above, electric field is dependent on position. The electric field due to any single charge falls off as the square of the distance from that charge.
• Electric fields follow the superposition principle. If more than one charge is present, the total electric field at any point is equal to the vector sum of the respective electric fields that each object would create in the absence of the others.
• 
• If this principle is extended to an infinite number of infinitesimally small elements of charge, the following formula results:
• 
• where
• ρ is the charge density, or the amount of charge per unit volume.

Your questions here (at CR4) have all been quite good, despite the assertions of others. They are by no means "too fundamental" or beneath us in some way. On the contrary, your question (for example) on multimeter digit resolution showed that most respondents were, in fact, clueless. There is tremendous value, in my opinion, to going beyond the obvious and continuing to ask "why?" (The best scientist devote lives to this.) I can assure you that you do not need to go very far down the path of such questioning before getting into areas that few (to zero) scientists and scarcely any engineers really understand. Those with only a tenuous grasp on the fundamental physics involved are often the first to criticize questions as being "too simple".

I can make electric and electronic devices work, but know almost nothing about how these things work on a fundamental basis. As far as I can tell, it's all magic.

Thank you so much MoronicBumble for your help.

That means if the current passing through a superconductor, there will not be EM propagation from the conductor. Is it right?