# Current in Magnetic fields

I have two magnetic fields question (high school level) which require clear answers...

1. When a current carrying conductor, such as a copper wire, is placed in a magnetic field it will experience a force. Has the force produced anything to do with the wire itself? if not, what produces the force? (I don't understand the highlighted bit....)

2. When a current carrying wire in a magnetic field experiences a force it is usually seen to move. Is this consistent with Newton's Third Law? Where is the equal and opposite force? Explain the observation.

My physics teach briefly explained it but I did not understand it fully..

Thank you.

• Re (1): write down the equation for the force per unit length on a wire carrying a current $I$ in a magnetic field $B$. Does the equation include anything to do with the wire e.g. it's diameter, the metal it's made of, etc? If the answer is no then the force does not have anything to do with the wire itself. Re (2): The force is between the wire and whatever is generating the magnetic field. For example if the field is from a permanent magnet the force is between the wire and the permanent magnet. – John Rennie May 30 '14 at 13:28