When to use it
Use it in electromagnetism problems to select the correct hand for Fleming's rule before finding the direction of force or current.
Example
For an electric motor (force from current in a magnetic field), use the left hand. For a generator (current from motion in a field), use the right hand.
Common mistake
Using the same hand for both. Left hand is for motors (current creates motion), right hand is for generators (motion creates current).
