Forces and fields question

Hey, for #1:

The force (called the Lorentz force) is proportional to the speed of the particle (in fact F=BQv.sin(theta) as you may know).

A good description of what is going on involves a lot of math's - look up Lorentz force for more details.

It can only be really explained from Einstein's Special Theory of Relativity as far as I know. This shows that when a charged particle is moving through a magnetic field, it experiences an electric field due to the relative motion.. The faster it goes, the bigger the 'apparent' electric field, This electric field causes the force; if the particle is stationary, the electric field is zero and there is no force.

For #2, electric and gravitational potential energies are both energies of position—they both depend on the location of charges or masses. They are different in that electrical potential energy depends on charge and gravitational potential energy depends on mass. An electron far from the nucleus will have the largest potential energy.

Thanks kittycat