ch21_arom


 * CHAPTER 21: MAGNETISM!**

B: Magnetic Field Strength (T) math \displaystyle F_{mag} math : Magnetic Force/Fore of Magnetic Field (N) q: Charge (C) v: velocity (m/s) I: Current (A) L: Length of Wire (m)
 * KEY VARIABLES:**

math \displaystyle F_{mag}=BIL math math \displaystyle B=\frac{F_{mag}}{qv} math
 * KEY EQUATIONS:**

SECTION 21-1 SECTION 21-2 SECTION 21-3
 * KEY CONCEPTS:**
 * Every magnet has two magnet poles, north and south
 * A magnetic dipole (a pair of magnetic poles) creates a magnetic field around it.
 * Magnetic field strength (B) is measured in tesla (T) which are N/A*m
 * A magnetic field flows from the north pole of the magnet to the south pole
 * If the magnetic field lines are coming out of the page they are represented by a solid circle.
 * If the magnetic field lines are going down into the page they are represented by a (x).
 * The magnetic north pole of the earth corresponds to the geographic south pole.
 * A magnetic field exists around any current carrying wire, the direction of the field around the wire follows a circular path according to the right hand rule
 * The right hand rule: If you point the thumb of your right hand in the direction of the current in wire and curl your fingers, the magnetic field will follow your fingers.
 * A solenoid or coil produces a magnetic field similar to the magnetic field created by a permanent magnet, the direction is once again determined by the right hand rule.
 * The right hand rule: If you wrap your fingers in the direction that the current flows in the coil then the magnetic field inside the coil will be in the direction of your thumb and will be nearly uniform within the coil.
 * Magnetic domain is a group of atoms whose magnetic fields are aligned.
 * In materials such as wood, plastic, etc. the magnetic fields of individual atoms are arranged randomly and cannot be aligned.
 * In materials such as iron, cobalt, and nickel the magnetic fields do not completely cancel and are known as ferromagnetic materials.
 * If a substance becomes magnetized by an external magnetic field, the individual domains are oriented to point in the same direction.
 * The domains will return to a random organization when the external field is removed if a material is easily magnetized.
 * If the material is not easily magnetized, the organization of the domains will remain when the external field is removed and the substance will remain magnetized.
 * The force created when a charge moves through a magnetic field has a maximum when the charge moved perpendicularly to the magnetic field, decreases at other angles, and becomes zero when the charge moves along the field lines.
 * The direction of the force on a positive charge moving through a magnetic field can be found using the right hand rule.
 * The right hand rule: If you point the fingers in the direction of the motion of the charge and then bend your fingers at an angle the force will be in the direction of your fingers. (If the charge is negative, find the direction for the positive charge and reverse it.)
 * If a charged particle is moving perpendicular to a uniform magnetic field, it's path will be circular.
 * The object will move in a helical path, with the velocity in the direction of its magnetic field unchanged, if the particle is not moving perpendicularly to the magnetic field.
 * Two current carrying wires that are parallel exert forces on another that are equal in magnitude but opposite in direction.
 * If the currents of two wires are in the same direction, they will attract each other.
 * If the currents of two wires are in opposite directions, they will repel each other.
 * Magnetic fields developed by conductors in the electric field are used to cause the needle to move in a galvanometer. They also produce sound heard over loudspeakers.

The organization and overall structure match the 2002 edition of __Holt Physics__ by Serway and Faughn and many of the expressions and the ideas come from there as well. Much of wording and ideas also come from __Honors Physics Review Notes 2008-2009__ by Strong.

Citations:

Faughn, Jerry S. and Raymond A. Serway. __Holt Physics.__ New York, Holt. 2002. Strong, Tom. Course notes. Honors Physics. Dept. of Science. Mt Lebanon High School. May and June 2009.