I was trying to understand how the electric & magnetic forces are related. I was going through the equations & the simple explanation of relativistic magnetic field given everywhere. Which goes like this... There is a current carrying conductor & a charge capable of moving outside it. The current is set up (velocity of electrons =v). Then the charge which is outside the wire moves with the same velocity. They say that due to length contraction, the force in charge's frame is electric force. (Charge density of positive charges increases & hence the net electric force). Suppose the charge is at rest & there's no current in the wire, will there be any electromagnetic force? Of course not. Now the current is set up..charge is stationary wrt to positive charges in the wire, does the charge experience a force?,well no.. But the electrons are moving. Their length has to contract. Giving rise to higher charge density & net electric force on the outside charge..but the charge doesn't experience a force... My question is where does this force go??