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# Magnetic

There are four different types of magnetism that a material can have: superconducting, diamagnetic, paramagnetic and lastly ferromagnetic. Superconducting materials are strongly repelled from permanent magnets. Diamagnetic materials are weakly repelled by permanent magnets. Paramagnetic materials are weakly attracted to permanent magnets. Ferromagnetic materials are strongly attracted to permanent magnets.

Only certain materials at very cold temperatures are superconductors. All materials experience diamagnetism, including skin and flowers. However it is a very weak effect so that we do not notice it in everyday life. Many materials are paramagnetic, such as oxygen and tungsten. But it is a very weak effect so we do not typically notice it. Only a few elements are ferromagnetic, including iron, cobalt and nickel.

Magnetics are used in various applications from industrial to commercial. They are used in credit and debit cards, in television and computers monitors, speakers, headphones and industrial magnetics to life things. Magnetics are also used in Hospitals in magnetic resonance imaging.

### Deriving a Magnetic Field in a Sphere Using Laplace's Equation

This solution derives the expression for the magnetic field inside the spherical shell with magnetic permeability mu and with an inner and outer radius of a and b, respectively. This object is placed in a uniform and constant magnetic field Ha. As this is a steady-state problem, no currents exist and the magnetic field H can be

### Condensed Matter Magnetism Problem

See the attached file. The existence of the surface of a piece of magnetizable material profoundly alters the internal magnetic field, H(int). Mostly this is a nuisance as in the demagnetization correction required to determine the true, (i.e. internal) susceptibility of a sample. Demagnetization can however be put to g

### Magnetic effects of current problem

Two high current transmission lines carry current of 25A and 75A in the same direction and are suspended parallel to each other 35cm apart. The vertical posts supporting these wires divide the lines into straight 15m segments. What magnetic force does each segment exert on the other.

### Finding an Impedance of Conducting Medium

Could you please assist with the problem attached? Thank you. Maxwell's equations for a homogeneous, isotropic, uncharged medium of conductivity, relative permittivity, and relative permeability lead to the expression: (see attachment) where E is the electric field. A linearly polarized plane wave of angular frequency w i