Magnetism

Magnetism

1. Greeks discovered lodestones that had the ability to attract themselves and metallic objects

   • Michael Faraday and Joseph Henry discovered electromagnetic induction
     • Alternators Electromagnets Relays

2. Magnetic Interaction

   • natural magnet, attracted small pieces of not magnetized iron
     • magnetism
       • object that exerts the magnetic force is known as magnet
   • regions of the magnet where there is more concentration of force are called magnetic poles.
     • law of magnetic force
       • equal magnetic poles repel and different poles attract
         • magnetic field is a vector field
           • any magnet is surrounded by a space in which magnetic effects are present
             • calculate the magnetic force
               • Force in a current carrying conductor
                 • velocity v
                 • force over the conductor

3. If an electric charge is at rest it produces an electric field only.

   • If the same electric charge is moving, it produces both an electric field and a magnetic field.
     • Oersted
       • the flow of a current passing through a wire caused the deviation of a compass
       • electromagnetism

4. principle for magnetic fields

   • The total magnetic field produced by several moving charges is the vector sum of the fields produced by individual charges
     • Biot-Savart formula
   • Hall effect sensor
     • measure magnetic fields and used to experimentally prove the calculations made with Biot-Savart
   • Long current-carrying conductor
     • Circular coil (center)
       • Circular coil with N number of windings (center)
       • Circular coil with N number of windings (any distance in the center axis)
         • Inside a solenoid

5. Ampere’s Law

   • elation between magnetic field and electric current

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