MCAT Physics

Magnetism

MCAT Physics > Magnetism

Background

Magnetic Fields (B) are created by a moving charge in an electric field. The further away from the charge the weaker the magnetic field

MCAT Magnetism - Magnetic Fields

Diamagnetic Materials are made of atoms with no unpaired electrons and have no net magnetic field. Are weakly anti-magnetic or non-magnetic because they can be repelled

Paramagnetic Materials have unpaired electrons and a dipole, but have a zero magnetic field due to orientation. They become weakly magnetized in the presence of an external field, which aligns the dipoles of the individual atoms with the magnetic field. Upon removal of external magnetic field, material will cease to be magnetized

Ferromagnetic Materials have unpaired electrons and permanent magnetic dipoles that are orientated randomly so there is no net dipole. They will become strongly magnetized when exposed to a magnetic field under certain temperatures

Curie Temperature is the crucial ferromagnetic temperature. When the ambient temperature is lower than Curie temperature, substance is permanently magnetized. Above the Curie temperature, the substance is paramagnetic

Current Carrying Wires create a magnetic field based on moving charge (current), which is equal to the sum of magnetic fields of all individual charges. Both wires create concentric circles of magnetic fields that are perpendicular to the wire. The strength decreases as distance from wire (radius) decreases.

Magnetic Fields of Straight Wires

B = (μ0i)/2πr

Magnetic Fields of Circular Loop Wires

B = (μ0i)/2r

Right Hand Rules

See Right Hand Rules

MCAT Physics

Physics Topics