(a) Direction of magnetic field produced around a straight current-carrying conductor is given by right-hand thumb rule. If we hold a current-carrying conductor in a right hand in such a way that the stretched thumb is along the direction of current, then the curly fingers around the conductor represent the direction of magnetic field lines.
(b) Direction of force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it, is given by Fleming’s left hand rule. Stretch the thumb, forefinger and middle finger of left hand in such a way that they are mutually perpendicular to each other. If the forefinger points to the direction of magnetic field and the middle finger points to the direction of current, then the thumb will point to the direction of motion or the force acting on the conductor.
