Conditions needed for magnetic force on a conductor

[Tane]

Homework Statement

Hello,

First question, does a conductor need to be carrying electric current, in order to experience a force from a magnetic field acting on it?

Secondly, why does a conductive element (e.g. a copper specimen) take longer to fall, when experiencing the magnetic field of the solenoid that it is falling through. Is the copper experiencing magnetic force and pressing against inside of solenoid, causing deceleration due to friction? How can this be if there is no initial current carried by copper?

Please assist me with understanding these scenarios, it would be much appreciated.
Thanks.

Relevant Equations

F = iLB sin(theta)
F = qvB
V=iR (possibly)

none

 

[rude man]

Problem Statement: Hello,

First question, does a conductor need to be carrying electric current, in order to experience a force from a magnetic field acting on it?

Yes. Only exception I can think of is with a moving wire with static charge on it.

Secondly, why does a conductive element (e.g. a copper specimen) take longer to fall, when experiencing the magnetic field of the solenoid that it is falling through. Is the copper experiencing magnetic force and pressing against inside of solenoid, causing deceleration due to friction? How can this be if there is no initial current carried by copper?

I can't think of any impeding force if a copper element falls thru a tube with B field parallel to the falling direction, as is the case with your solenoid. Even if the element carried net charge.

 

[neilparker62]

A straight conducter moving perpendicular to a fixed magnetic field generates its own current (movement of charge) which then causes a force opposìng the original motion. This is essentially Lenz's law and - in one way or another - explains slowing of a charge carrier (e.g. copper coin) moving in a magnetic field.