Magnetism
A magnetic field is produced any time an ion has a velocity. This means that’s circuits create a magnetic field (as long as there is potential), permanent bar magnets obvious have a magnetic field, and it also means that a proton or electron with a velocity will create its own magnetic field!
The equation for magnetic force is F = qvBsinθ where q is the charge, v is the velocity, and B is the magnitude of the magnetic field. Sinθ shows that at 90 degrees, the force will be the largest. If the velocity and magnetic field direction are parallel or anti-parallel, the force will be ZERO! If you solve for B you find N/A*m = Tesla (T). 1 Gauss = 10^4 Tesla
I’m not going to go into the right hand rule because that would be way to confusing to type out.
A few important points. Many times, a charged particle will end up experiencing centripetal acceleration due to a magnetic field. You can set the two equations equation to each other. mv^2/r = qvB, r=mv/qB. As the mass and velocity increase, so does the radius. As the charge and magnetic field increase, the radius decreases. Next, if a charge moves through an area that has both an electric field and a magnetic field, the net force will be the sum of both forces. F=qE and F = qvB = q(E + vB).
The Earth has it’s own magnetic field as well. We all know the geographic north and south poles. Since magnetic field lines exit the north and enter the south, a compass actually points north when referring to the geographic south pole!. Therefore, the Earth’s magnetic north is the same as the geographic north and vice-versa.
A few extra points about magnetism:
1. Iron is special and is “ferromagnetic” because it creates its own magnetic field that is constant without the influence of an external magnetic field. Refrigerator magnets are an example of ferromagnetism.
2. Diamagnetic species have full paired electron shells. For example Mg is diamagnetic because it’s 1s2 and 2s2 shells both have paired electrons. In the presence of an external magnetic field, these species will be deflected away (repelled)! (remember D for deflected)
3. Paramagnetic species have an odd number of electrons AND have an empty orbital. Li,C,N,O just to name a few. In the presence of an external magnetic field, they will be deflected towards it (attracted).
