Source: http://s0a05578cbddcd72c.jimcontent.com/download/version/1436360995/module/9627641252/name/S%C3%A9rie%20d'exercices%20N%C2%B05%20-%20Physique%20champ%20magnetique%20-%203%C3%A8me%20Sciences%20exp%20(2013-2014)%20Mr%20GHARBIA%20MOHAMED.pdf