Fleming's left hand rule : The direction of force which acts on the current carrying conductor placed in a magnetic field is given by Fleming's left hand rule. It states that if the forefinger, thumb and middle finger of left hand are stretched mutually perpendicular and the forefinger point along the direction of external magnetic field, middle finger indicates the direction of current, then thumb points along the direction of force acting on the conductor.
Example : When an electron enters a magnetic field at right angles, the direction of force on electron is perpendicular to the direction of magnetic filed and current according to this rule.
