Right Hand Rules # 1 & 2

The right hand rule (or RHR) is a useful little rule for determining the direction of the magnetic field. The Right-hand rule #1 is used for a conventional current to determine the direction of current flow and magnetic field in a conductor. Depending on the information given, you either point your thumb in the direction of the current flow, or coil your fingers so that they point in the direction of the magnetic field. Using the rule, one can figure out which way current flows or which way the magnetic field turns.

 

For example, in the above diagram, if I only knew the current flowed upwards I would point my thumb up and grab the conductor. The direction my fingers coil is the direction the magnetic field is in.

RHR # 2 is used for coils. In a coiled conductor or solenoid, the thumb will always point to the north pole of the magnet and the fingers will point in the direction of current flow. Inside the coil, the thumb also represents the direction of the magnetic field. 

The left hand rules are similar to the right hand rules, except they are used for electron currents, or when the charge flows from negative to positive.