The various FBI mnemonics (for electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s) show the direction of the force

Force

In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

 on a conductor

Electrical conductor

In physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...

 carrying a current

Electric current

Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

 in a magnetic field

Magnetic field

A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

.

Other mnemonics exist that use a right hand rule for predicting resulting motion from a preexisting current and field.

'FBI'

The left hand is held with the thumb

Thumb

The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...

, first finger and second finger mutually at right angles.

• The Thumb represents F - Thrust (or resulting Motion).

• The First finger represents B - Field.

• The Second finger represents I or V - Current (in the classical direction, from positive to negative).

Configuration, using the right hand

Other sources use the right hand to predict force, though the fingers used vary:

'FIB'

• Thumb = F ("thrust")
• Index finger = I or V
• Middle finger ("Birdie
  Finger (gesture)
  In Western culture, the finger , also known as the middle finger, is an obscene hand gesture, often meaning the phrases "fuck off" , "fuck you" or "up yours"...
  
  ") = B

'IBF'

In this alternative, some versions recommend not extending the middle finger, but instead imagining the force coming from the palm of the hand.

• Thumb = I or V
• Index finger
  Index finger
  The index finger, , is the first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger...
  
   = B
• Middle finger
  Middle finger
  The middle finger or long finger is the third digit of the human hand, located between the index finger and the ring finger. It is usually the longest finger...
  
   = F

Prediction of direction of field ('B')

The rules above are usually used to predict 'F' based upon 'B' and 'I' - the force on a moving charge when moving through a field, whether or not the charge is carried in a wire. However, this rule should not be confused with a different right hand grip rule for the prediction of the direction of a field ('B') produced by current ('I') traveling through a wire.

Symmetry

Vector	Left-Motor or Right-Generator	Left-Motor or Right-Generator	Left-Motor or Right-Generator	Right-Motor or Left-Generator	Right-Motor or Left-Generator	Right-Motor or Left-Generator
B or Field	First or Index	Thumb	Fingers or Palm	First or Index	Thumb	Fingers or Palm
I or Current (+ to - flow)	Fingers or Palm	First or Index	Thumb	Thumb	Fingers or Palm	First or Index
Force, Motion, or Thrust	Thumb	Fingers or Palm	First or Index	Fingers or Palm	First or Index	Thumb

External links

• Overview at ac.wwu.edu (Right Hand - 'FIB')
• Diagrams at magnet.fsu.edu. See figure #9. (Left Hand - 'FBI')
• Description at starprof.com (Right Hand - 'IBF' - palm alternative)