1. Magnetism From Electricity

2. Magnetic Field of a Current Carrying Wire
1820 – Hans Christian Øersted – demonstrated that a current carrying wire would deflect a compass needle
Proved the relationship between electricity and magnetism
A long, straight current carrying wire has a cylindrical magnetic field
Compass needles will point in a circle surrounding the wire in the direction of the induced magnetic field
Use the right hand rule to determine the direction of the magnetic field
If you point your right thumb in the direction of current
Your fingers coil in the direction of the magnetic field
The magnitude of the magnetic field, B, is the same for every point on a circular path for a given distance from the wire, lying in a plane perpendicular to the wire
Directly proportional to the current in the wire and inversely proportional to the distance from the wire

3. Magnetic Field of a Current Carrying Wire

4. Magnetic Field of a Current Carrying Wire

5. Magnetic Field of a Current Carrying Wire

6. Magnetic Field of a Current Loop
The right hand rule can also be used to determine the direction of the magnetic field in a current carrying loop
As long as the thumb is pointed in the direction of current, the fingers will curl in the direction of the magnetic field
Solenoid – a long, helically wound coil of insulated wire
Acts as a magnet when it carries a current
The more loops in the solenoid and the stronger the current, the greater the magnetic field
Inserting an iron rod into the center of the coil increases the magnetic field and produces an electromagnet
Uniform magnetic field inside the solenoid, and a variable magnetic field outside the solenoid
Used in many household appliances, automobiles, medical equipment

7. Magnetic Field of a Current Loop
Magnetic Field in a Current Carrying Loop

8. Magnetic Field of a Current Loop