Explain zero force acting on a wire which is not carrying current,on being placed inside a magnetic field.
Asked Praagy Shukla
A charge at rest will not experience any force in a magnetic field, but a moving charge will experience a force unless it is moving parallel to the field.
In a conductor, the electrons are in rapid and random motion, but the conductor will not experience a force until a current is passing through it. (Even though the electrons are not at rest). This is because, in the absence of a current, the motion of electrons is random and there is no net drift of electrons in any direction. Thus the forces cancel out.
When a current is passed through the wire, there is a net drift and hence a net force is experienced by the current carrying conductor in a magnetic field.
Further, I want to mention that the force is experienced between the existing field and the field produced by the moving charges/ current.