Assume a charge of +Q and -Q on each conductor
Find the electric field between the conductors (Gauss's Law)
Since the magnetic force is always perpendicular to the object’s velocity, it does zero work on any charged particle.
Zero work means zero change in kinetic energy, so the speed remains the same.
Remember: The magnetic force can only change the direction of a charged particle’s velocity, not its speed.
![If a conducting sphere contains a charge of + q within an inner cavity, a charge of —q will move to the wall of the cavity to "guard" the inte- rior of the sphere from an electrostatic field, regardless of the size, shape, or location of the cavity. As a result, a charge of +q is left on the exterior of the sphere (and it will be uniform). So, at points outside the sphere, the sphere behaves as if this charge
- q were concentrated at its center, so the electric field outside is simply kQ/r . Since points X and Y are at the same distance from the center of the sphere, the elec- tric field strength at Y will be the same as at X. ](./media/image624.png)