Current: the transfer of positive charge; the opposite of electron flow.
Electromagnetism: the interactions between electric currents and magnetic fields
Background Information
- In 1819, a Danish physicist named Hans Oersted discovered that a current-carrying conductor caused a magnetic compass to deflect. This led him to be credited for the discovery of electromagnetism.
- Electromagnetic fields can be created by the movement of charges, but not by static charges.
Right hand rule #1
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| Thumb points toward the current, fingers encircling the conductor in the direction of the magnetic lines of force |
Magnetic Field Theory
- Magnetic field is the source of magnetic forces
- A current creates a magnetic field around itself
- The strength of the magnetic field is directly related to the strength of the current
Magnetic Field of a Current-Carrying coil
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| Arrow is the direction of the current; x's are the magnetic fields coming into the page; dots are the magnetic field coming out of the page |
As shown in the picture, the field inside the loop is stronger than the field outside of the loop. Also, the field is more uniformed inside the loop
