Fleming’s Left hand rule gives the direction of force on a current carrying conductor placed perpendicular to the magnetic field.

Fleming’s Left hand rule: According to this rule, stretch the thumb, fore-finger and middle finger of left hand such that they are mutually perpendicular. If the middle finger points in the direction of the magnetic field, the fore-finger points in the direction of flow of current, then the thumb points in the direction of motion i.e., force acting on the conductor.

Figure below illustrates it.