Left+Hand+Rule

Left Hand Rule #1
This rule is used to determine either the magnetic field or the current traveling around a rod of some sort. This is the only case in which this rule applies.

Pretend you are wrapping your fingers around an imaginary rod curing the fingers in the direction of the Magnetic field (B-field). The thumb will then point in the direction of the current (I). This is shown in the diagram below.



Left Hand Rule #2
This rule is used to determine the direction of the current along with the direction of the magnetic field which you can find out which way is moving as it will also follow the thumb just as in the first LHR. Wrap your fingers around the solenoid (Below) so that your fingers are traveling the same direction as the current (I). This can be tricky sometimes because you have to envision your fingers curling behind the solenoid and coming back around the bottom. Extend your thumb along the cylinder object. As long as the current continues to flow in the direction your fingers are curled, your thumb will always point toward the north pole. Look at the above diagram to get a sense of it, except the rod would be a solenoid and the direction the thumb is pointing is to the north pole.

Left Hand Rule #3
This will be the most used hand rule throughout physics 30. This rule shows the magnetic field, the force, and the current of velocity of the object.

This rule is used to describe a force when current or electrons are run through a magnetic field. To find the direction, you open your palm and make your thumb perpendicular to your fingers. Your thumb represents the direction of the current or the velocity of the electric charge (I). Then bend your middle, ring and pinky finger to be perpendicular to both the index and thumb. These three fingers will represent the direction of the force against the object. The Index finger should still be sticking straight out. This will show the direction of the magnetic field. Remember, when you apply these rules, you have six basic vectors to work with (up, down, left, right, into, out of).
 * This only works for** __negatively__ **charged particles***


 * Use the same fingers set up with the** __Right Hand__ **for** __Positively__ **charged particles***

//References//

 * 1) LD's Notes on Magnetism