{"id":1593,"date":"2026-09-08T08:07:14","date_gmt":"2026-09-08T08:07:14","guid":{"rendered":"https:\/\/maroczain.com\/scolaire.maroczain.com\/?page_id=1593"},"modified":"2026-09-08T08:07:14","modified_gmt":"2026-09-08T08:07:14","slug":"magnetostatique-cpge","status":"publish","type":"page","link":"https:\/\/maroczain.com\/scolaire.maroczain.com\/magnetostatique-cpge\/","title":{"rendered":"Magn\u00e9tostatique CPGE."},"content":{"rendered":"\n&#8220;`html\n<div id=\"mza-magnetostatique-cpge\">\n\n<style>\n#mza-magnetostatique-cpge,#mza-magnetostatique-cpge *{box-sizing:border-box}\n#mza-magnetostatique-cpge{\n --navy:#06172c;--navy2:#0d416d;--gold:#c99a36;--gold2:#efd68c;\n --paper:#f5f6f8;--white:#fff;--text:#18283a;--muted:#687789;--line:#dfe5eb;\n font-family:Arial,Helvetica,sans-serif;background:var(--paper);color:var(--text);overflow:hidden\n}\n#mza-magnetostatique-cpge a{text-decoration:none;color:inherit}\n#mza-magnetostatique-cpge .wrap{max-width:1200px;margin:auto;padding:0 24px}\n#mza-magnetostatique-cpge section{padding:68px 0}\n#mza-magnetostatique-cpge .hero{\n color:#fff;padding:72px 0;\n background:\n radial-gradient(circle at 84% 15%,rgba(213,169,68,.28),transparent 28%),\n linear-gradient(135deg,#041224,#082b4c 65%,#10517e)\n}\n#mza-magnetostatique-cpge .badge{\n display:inline-block;padding:8px 13px;border-radius:999px;\n border:1px solid rgba(239,214,140,.4);color:var(--gold2);\n font-size:11px;font-weight:900;letter-spacing:1.3px\n}\n#mza-magnetostatique-cpge h1{\n font:500 clamp(42px,7vw,72px)\/1 Georgia,serif;margin:17px 0;color:#fff\n}\n#mza-magnetostatique-cpge .lead{max-width:900px;color:#d5e1ea;font-size:18px;line-height:1.75}\n#mza-magnetostatique-cpge .actions{display:flex;gap:9px;flex-wrap:wrap;margin-top:26px}\n#mza-magnetostatique-cpge .btn{\n min-height:47px;padding:0 18px;border:none;border-radius:10px;\n display:inline-flex;align-items:center;justify-content:center;cursor:pointer;\n font-size:12px;font-weight:900\n}\n#mza-magnetostatique-cpge .gold{background:linear-gradient(135deg,#bd892b,#efd483);color:#142238}\n#mza-magnetostatique-cpge .glass{background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.18);color:#fff}\n#mza-magnetostatique-cpge .head{max-width:880px;margin-bottom:32px}\n#mza-magnetostatique-cpge .kicker{color:#987023;font-size:11px;font-weight:900;letter-spacing:1.3px}\n#mza-magnetostatique-cpge h2{\n color:var(--navy);font:500 clamp(31px,4vw,48px)\/1.1 Georgia,serif;margin:8px 0 11px\n}\n#mza-magnetostatique-cpge .head p{color:var(--muted);line-height:1.7}\n#mza-magnetostatique-cpge .grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}\n#mza-magnetostatique-cpge .grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}\n#mza-magnetostatique-cpge .card{\n background:#fff;border:1px solid var(--line);border-radius:19px;padding:23px\n}\n#mza-magnetostatique-cpge .card h3{color:var(--navy);margin:0 0 10px;font-size:20px}\n#mza-magnetostatique-cpge .card p,#mza-magnetostatique-cpge .card li{color:var(--muted);line-height:1.7}\n#mza-magnetostatique-cpge .formula{\n margin:14px 0;padding:15px;border-left:4px solid var(--gold);\n background:#f8f6ef;border-radius:0 12px 12px 0;\n font-family:Georgia,serif;color:#213349;line-height:1.75\n}\n#mza-magnetostatique-cpge .tip{\n margin-top:14px;padding:13px;border-radius:11px;background:#eef3f7;\n color:#40546a;font-size:13px;line-height:1.6\n}\n#mza-magnetostatique-cpge .dark{background:var(--navy);color:#fff}\n#mza-magnetostatique-cpge .dark h2{color:#fff}\n#mza-magnetostatique-cpge .dark .head p{color:#c6d4df}\n#mza-magnetostatique-cpge .method{display:grid;grid-template-columns:repeat(6,1fr);gap:10px}\n#mza-magnetostatique-cpge .method div{\n padding:20px 10px;text-align:center;border-radius:14px;\n background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.1)\n}\n#mza-magnetostatique-cpge .method b{display:block;color:var(--gold2);font-size:23px;margin-bottom:7px}\n#mza-magnetostatique-cpge .method span{font-size:10px;font-weight:900}\n#mza-magnetostatique-cpge .exercise{\n background:#fff;border:1px solid var(--line);border-radius:18px;padding:22px;margin-bottom:14px\n}\n#mza-magnetostatique-cpge .exercise h3{color:var(--navy);margin:0 0 10px}\n#mza-magnetostatique-cpge .level{\n display:inline-block;padding:6px 9px;margin-bottom:10px;border-radius:999px;\n background:#f1eee5;color:#7b5b1d;font-size:10px;font-weight:900\n}\n#mza-magnetostatique-cpge .exercise p{color:var(--muted);line-height:1.7}\n#mza-magnetostatique-cpge .hint{\n display:none;margin-top:12px;padding:15px;border-radius:12px;\n background:#eef3f7;color:#425469;line-height:1.65\n}\n#mza-magnetostatique-cpge .qcm{\n background:#fff;border:1px solid var(--line);border-radius:23px;padding:28px\n}\n#mza-magnetostatique-cpge .question{\n padding:20px;margin:15px 0;background:#f7f8fa;border-radius:14px\n}\n#mza-magnetostatique-cpge .question strong{display:block;color:var(--navy);margin-bottom:12px}\n#mza-magnetostatique-cpge label{display:block;padding:8px 0;color:#526174;cursor:pointer}\n#mza-magnetostatique-cpge #magResult{\n display:none;margin-top:18px;padding:20px;border-radius:14px;background:var(--navy);color:#fff\n}\n#mza-magnetostatique-cpge .cta{\n text-align:center;padding:50px 24px;border-radius:25px;\n background:linear-gradient(135deg,#06172c,#0d416d);color:#fff\n}\n#mza-magnetostatique-cpge .cta h2{color:#fff}\n#mza-magnetostatique-cpge .cta p{max-width:760px;margin:0 auto 22px;color:#cfdae4;line-height:1.7}\n\n@media(max-width:900px){\n #mza-magnetostatique-cpge .grid,\n #mza-magnetostatique-cpge .grid3,\n #mza-magnetostatique-cpge .method{grid-template-columns:1fr}\n}\n<\/style>\n\n<header class=\"hero\">\n<div class=\"wrap\">\n\n<span class=\"badge\">COURS 08 \u2022 PHYSIQUE CPGE<\/span>\n\n<h1>Courants.<br>Champs. Trajectoires.<\/h1>\n\n<p class=\"lead\">\nLa magn\u00e9tostatique d\u00e9crit les champs cr\u00e9\u00e9s par des courants stationnaires.\nForce de Lorentz, Biot-Savart, Amp\u00e8re, sol\u00e9no\u00efdes et moments magn\u00e9tiques\nforment un ensemble central de l&#8217;\u00e9lectromagn\u00e9tisme CPGE.\n<\/p>\n\n<div class=\"actions\">\n<a href=\"#cours\" class=\"btn gold\">\ud83d\udcda COMMENCER<\/a>\n<a href=\"#methode\" class=\"btn glass\">\ud83e\udde0 M\u00c9THODE<\/a>\n<a href=\"#exercices\" class=\"btn glass\">\ud83e\udde9 EXERCICES<\/a>\n<a href=\"#qcm\" class=\"btn glass\">\u2753 QCM<\/a>\n<\/div>\n\n<\/div>\n<\/header>\n\n<section id=\"cours\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">1. CHAMP MAGN\u00c9TIQUE<\/span>\n<h2>Une grandeur vectorielle cr\u00e9\u00e9e notamment par les courants.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>Notation<\/h3>\n<div class=\"formula\">B<\/div>\n<p>Le champ magn\u00e9tique est un vecteur.<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Unit\u00e9 SI<\/h3>\n<div class=\"formula\">tesla (T)<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Lignes de champ<\/h3>\n<p>\nElles sont tangentes au vecteur B en chaque point.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Propri\u00e9t\u00e9<\/h3>\n<p>\nLes lignes de champ magn\u00e9tique sont ferm\u00e9es : on ne rencontre pas de monop\u00f4le magn\u00e9tique dans le cadre classique usuel.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">2. FORCE DE LORENTZ<\/span>\n<h2>Action d&#8217;un champ magn\u00e9tique sur une charge en mouvement.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<div class=\"formula\">\nF = q(E + v \u00d7 B)\n<\/div>\n\n<p>\nDans un champ purement magn\u00e9tique :\n<\/p>\n\n<div class=\"formula\">\nF = q v \u00d7 B\n<\/div>\n\n<p>\nSa norme vaut :\n<\/p>\n\n<div class=\"formula\">\nF = |q|vB sin \u03b8\n<\/div>\n\n<\/div>\n\n<div class=\"tip\">\nLa force magn\u00e9tique est toujours perpendiculaire \u00e0 la vitesse instantan\u00e9e. Elle ne travaille donc pas.\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">3. MOUVEMENT DANS UN CHAMP UNIFORME<\/span>\n<h2>Le champ change la direction, pas la norme de la vitesse.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>Si v \u27c2 B<\/h3>\n<p>\nLe mouvement est circulaire uniforme.\n<\/p>\n\n<div class=\"formula\">\nR = mv \/ (|q|B)\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Pulsation cyclotron<\/h3>\n\n<div class=\"formula\">\n\u03c9<sub>c<\/sub> = |q|B\/m\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>P\u00e9riode<\/h3>\n\n<div class=\"formula\">\nT = 2\u03c0m\/(|q|B)\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Si v poss\u00e8de une composante parall\u00e8le<\/h3>\n<p>\nLa trajectoire devient h\u00e9lico\u00efdale.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section id=\"methode\" class=\"dark\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\" style=\"color:#efd68c\">MZA MAGNETIC ENGINE<\/span>\n<h2>La m\u00e9thode avant tout calcul de champ.<\/h2>\n<\/div>\n\n<div class=\"method\">\n<div><b>01<\/b><span>SOURCE<\/span><\/div>\n<div><b>02<\/b><span>SYM\u00c9TRIES<\/span><\/div>\n<div><b>03<\/b><span>DIRECTION<\/span><\/div>\n<div><b>04<\/b><span>SENS<\/span><\/div>\n<div><b>05<\/b><span>BIOT \/ AMP\u00c8RE<\/span><\/div>\n<div><b>06<\/b><span>LIMITES<\/span><\/div>\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">4. LOI DE BIOT-SAVART<\/span>\n<h2>Construire le champ \u00e0 partir d&#8217;un \u00e9l\u00e9ment de courant.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un \u00e9l\u00e9ment de courant I dl :\n<\/p>\n\n<div class=\"formula\">\ndB =\n(\u03bc\u2080 \/ 4\u03c0) \u00b7 I (dl \u00d7 u<sub>r<\/sub>) \/ r\u00b2\n<\/div>\n\n<p>\nLe champ total s&#8217;obtient par int\u00e9gration :\n<\/p>\n\n<div class=\"formula\">\nB = \u222b dB\n<\/div>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">5. FIL RECTILIGNE INFINI<\/span>\n<h2>Un grand classique de sym\u00e9trie cylindrique.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\n\u00c0 une distance r d&#8217;un fil infini parcouru par un courant I :\n<\/p>\n\n<div class=\"formula\">\nB(r) = \u03bc\u2080I \/ (2\u03c0r)\n<\/div>\n\n<p>\nLe champ est tangent aux cercles centr\u00e9s sur le fil.\n<\/p>\n\n<div class=\"tip\">\nLe sens se d\u00e9termine avec la r\u00e8gle de la main droite.\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">6. TH\u00c9OR\u00c8ME D&#8217;AMP\u00c8RE<\/span>\n<h2>L&#8217;\u00e9quivalent magn\u00e9tique de Gauss pour certaines sym\u00e9tries.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<div class=\"formula\">\n\u222e B \u00b7 dl = \u03bc\u2080 I<sub>enlac\u00e9<\/sub>\n<\/div>\n\n<p>\nLe th\u00e9or\u00e8me d&#8217;Amp\u00e8re devient tr\u00e8s efficace pour :\n<\/p>\n\n<ul>\n<li>fil rectiligne infini ;<\/li>\n<li>sol\u00e9no\u00efde long ;<\/li>\n<li>tore id\u00e9al ;<\/li>\n<li>distributions pr\u00e9sentant une forte sym\u00e9trie.<\/li>\n<\/ul>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">7. SOL\u00c9NO\u00cfDE LONG<\/span>\n<h2>Cr\u00e9er un champ presque uniforme.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un sol\u00e9no\u00efde long comportant n spires par unit\u00e9 de longueur :\n<\/p>\n\n<div class=\"formula\">\nB \u2248 \u03bc\u2080 n I\n<\/div>\n\n<p>\n\u00e0 l&#8217;int\u00e9rieur, loin des extr\u00e9mit\u00e9s.\n<\/p>\n\n<p>\nLe champ ext\u00e9rieur est beaucoup plus faible dans le mod\u00e8le id\u00e9al.\n<\/p>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">8. TORE<\/span>\n<h2>Champ confin\u00e9 par sym\u00e9trie.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un tore id\u00e9al de N spires parcourues par un courant I :\n<\/p>\n\n<div class=\"formula\">\nB(r) = \u03bc\u2080NI \/ (2\u03c0r)\n<\/div>\n\n<p>\ndans la r\u00e9gion magn\u00e9tique interne du tore.\n<\/p>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">9. FORCE SUR UN CONDUCTEUR<\/span>\n<h2>Du mouvement des charges \u00e0 la force de Laplace.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un \u00e9l\u00e9ment de conducteur :\n<\/p>\n\n<div class=\"formula\">\ndF = I dl \u00d7 B\n<\/div>\n\n<p>\nPour une portion rectiligne de longueur L plong\u00e9e dans un champ uniforme :\n<\/p>\n\n<div class=\"formula\">\nF = I L \u00d7 B\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">10. COUPLE SUR UNE SPIRE<\/span>\n<h2>Transformer un champ magn\u00e9tique en rotation.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nUne spire plane de surface S parcourue par un courant I poss\u00e8de un moment magn\u00e9tique :\n<\/p>\n\n<div class=\"formula\">\nm = I S n\n<\/div>\n\n<p>\nLe couple exerc\u00e9 par un champ B vaut :\n<\/p>\n\n<div class=\"formula\">\n\u0393 = m \u00d7 B\n<\/div>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">11. \u00c9NERGIE D&#8217;UN DIP\u00d4LE MAGN\u00c9TIQUE<\/span>\n<h2>Orientation privil\u00e9gi\u00e9e dans le champ.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<div class=\"formula\">\nE<sub>p<\/sub> = -m \u00b7 B\n<\/div>\n\n<p>\nL&#8217;\u00e9nergie est minimale lorsque m est align\u00e9 avec B.\n<\/p>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">12. SYM\u00c9TRIES MAGN\u00c9TIQUES<\/span>\n<h2>Analyser la g\u00e9om\u00e9trie avant l&#8217;int\u00e9grale.<\/h2>\n<\/div>\n\n<div class=\"grid3\">\n\n<div class=\"card\">\n<h3>Fil infini<\/h3>\n<p>\nInvariance par translation le long du fil et rotation autour de son axe.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Sol\u00e9no\u00efde long<\/h3>\n<p>\nApproximation d&#8217;invariance par translation loin des extr\u00e9mit\u00e9s.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Tore<\/h3>\n<p>\nSym\u00e9trie circulaire autour de l&#8217;axe du tore.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">13. R\u00c8GLE DE LA MAIN DROITE<\/span>\n<h2>D\u00e9terminer rapidement le sens du champ.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>Fil rectiligne<\/h3>\n<p>\nPouce dans le sens du courant, doigts enroul\u00e9s dans le sens du champ.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Spire<\/h3>\n<p>\nDoigts dans le sens du courant, pouce dans le sens du moment magn\u00e9tique.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section id=\"exercices\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">14. EXERCICES PROGRESSIFS<\/span>\n<h2>Direction, norme, mouvement.<\/h2>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU 1<\/span>\n\n<h3>Exercice 1 \u2014 Charge dans un champ<\/h3>\n\n<p>\nUne particule de charge q p\u00e9n\u00e8tre avec une vitesse v perpendiculaire\n\u00e0 un champ magn\u00e9tique uniforme B.\nIdentifier la nature de la trajectoire.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaMagHint('magHint1')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"magHint1\" class=\"hint\">\nLa force magn\u00e9tique est toujours perpendiculaire \u00e0 la vitesse et sa norme reste constante.\n<\/div>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU 2<\/span>\n\n<h3>Exercice 2 \u2014 Rayon cyclotron<\/h3>\n\n<p>\nD\u00e9terminer le rayon de courbure d&#8217;une particule de masse m et de charge q\nse d\u00e9pla\u00e7ant \u00e0 vitesse v perpendiculairement \u00e0 B.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaMagHint('magHint2')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"magHint2\" class=\"hint\">\nIdentifiez la force magn\u00e9tique \u00e0 la r\u00e9sultante centrip\u00e8te.\n<\/div>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU 3<\/span>\n\n<h3>Exercice 3 \u2014 Champ d&#8217;un fil<\/h3>\n\n<p>\nUn fil rectiligne infini est parcouru par un courant I.\nD\u00e9terminer B \u00e0 une distance r.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaMagHint('magHint3')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"magHint3\" class=\"hint\">\nChoisissez comme contour d&#8217;Amp\u00e8re un cercle centr\u00e9 sur le fil.\n<\/div>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU PR\u00c9PA<\/span>\n\n<h3>Exercice 4 \u2014 Sol\u00e9no\u00efde<\/h3>\n\n<p>\nUn sol\u00e9no\u00efde long poss\u00e8de N spires sur une longueur L et est parcouru par un courant I.\nRetrouver le champ int\u00e9rieur.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaMagHint('magHint4')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"magHint4\" class=\"hint\">\nIntroduisez la densit\u00e9 de spires n=N\/L puis utilisez le th\u00e9or\u00e8me d&#8217;Amp\u00e8re.\n<\/div>\n<\/div>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">15. PROBLEM LAB<\/span>\n<h2>Mission : spectrom\u00e8tre magn\u00e9tique.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<h3>Situation<\/h3>\n\n<p>\nDes ions de m\u00eame charge q mais de masses diff\u00e9rentes p\u00e9n\u00e8trent avec la m\u00eame vitesse v\ndans une r\u00e9gion o\u00f9 r\u00e8gne un champ magn\u00e9tique uniforme B perpendiculaire \u00e0 leur vitesse.\n<\/p>\n\n<p>Votre mission :<\/p>\n\n<ol>\n<li>faire le bilan des forces ;<\/li>\n<li>justifier que la norme de la vitesse reste constante ;<\/li>\n<li>montrer que la trajectoire est circulaire ;<\/li>\n<li>exprimer le rayon en fonction de m, q, v et B ;<\/li>\n<li>comparer les rayons de deux isotopes de masses diff\u00e9rentes ;<\/li>\n<li>expliquer comment le dispositif permet de s\u00e9parer les ions ;<\/li>\n<li>\u00e9tudier l&#8217;effet d&#8217;une augmentation de B ;<\/li>\n<li>\u00e9tudier l&#8217;effet du signe de q sur le sens de courbure ;<\/li>\n<li>v\u00e9rifier l&#8217;homog\u00e9n\u00e9it\u00e9 de l&#8217;expression du rayon.<\/li>\n<\/ol>\n\n<div class=\"actions\">\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaMagHint('magMission1')\">\ud83d\udca1 INDICE<\/button>\n<button type=\"button\" class=\"btn\" style=\"background:#06172c;color:#fff\" onclick=\"mzaMagHint('magMission2')\">\ud83e\udde0 M\u00c9THODE<\/button>\n<\/div>\n\n<div id=\"magMission1\" class=\"hint\">\nLa force magn\u00e9tique poss\u00e8de la bonne direction pour jouer le r\u00f4le de force centrip\u00e8te.\n<\/div>\n\n<div id=\"magMission2\" class=\"hint\">\n\u00c9crivez |q|vB = mv\u00b2\/R. Le reste devient une analyse comparative entre masse, charge, vitesse, champ et rayon.\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section class=\"dark\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\" style=\"color:#efd68c\">MZA MAGNETIC CHECK<\/span>\n<h2>Les six r\u00e9flexes magn\u00e9tostatiques.<\/h2>\n<\/div>\n\n<div class=\"method\">\n<div><b>A<\/b><span>COURANT<\/span><\/div>\n<div><b>B<\/b><span>SYM\u00c9TRIE<\/span><\/div>\n<div><b>C<\/b><span>DIRECTION<\/span><\/div>\n<div><b>D<\/b><span>SENS<\/span><\/div>\n<div><b>E<\/b><span>AMP\u00c8RE<\/span><\/div>\n<div><b>F<\/b><span>LORENTZ<\/span><\/div>\n<\/div>\n\n<\/div>\n<\/section>\n\n<section id=\"qcm\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">16. QCM DE VALIDATION<\/span>\n<h2>Diagnostic Magn\u00e9tostatique CPGE.<\/h2>\n<p>Le score est affich\u00e9 sans r\u00e9v\u00e9ler les r\u00e9ponses correctes.<\/p>\n<\/div>\n\n<div class=\"qcm\">\n\n<form id=\"magQuiz\">\n\n<div class=\"question\">\n<strong>1. La force magn\u00e9tique sur une charge q vaut :<\/strong>\n<label><input type=\"radio\" name=\"m1\" value=\"1\"> q v \u00d7 B<\/label>\n<label><input type=\"radio\" name=\"m1\" value=\"0\"> qB\/v<\/label>\n<label><input type=\"radio\" name=\"m1\" value=\"0\"> qvB sans direction<\/label>\n<label><input type=\"radio\" name=\"m1\" value=\"0\"> qE uniquement<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>2. Une force magn\u00e9tique pure :<\/strong>\n<label><input type=\"radio\" name=\"m2\" value=\"1\"> ne modifie pas l&#8217;\u00e9nergie cin\u00e9tique<\/label>\n<label><input type=\"radio\" name=\"m2\" value=\"0\"> augmente toujours la vitesse<\/label>\n<label><input type=\"radio\" name=\"m2\" value=\"0\"> diminue toujours la vitesse<\/label>\n<label><input type=\"radio\" name=\"m2\" value=\"0\"> est parall\u00e8le \u00e0 la vitesse<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>3. Le champ cr\u00e9\u00e9 par un fil rectiligne infini varie comme :<\/strong>\n<label><input type=\"radio\" name=\"m3\" value=\"1\"> 1\/r<\/label>\n<label><input type=\"radio\" name=\"m3\" value=\"0\"> 1\/r\u00b2<\/label>\n<label><input type=\"radio\" name=\"m3\" value=\"0\"> r<\/label>\n<label><input type=\"radio\" name=\"m3\" value=\"0\"> r\u00b2<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>4. Le th\u00e9or\u00e8me d&#8217;Amp\u00e8re s&#8217;\u00e9crit :<\/strong>\n<label><input type=\"radio\" name=\"m4\" value=\"1\"> \u222eB\u00b7dl = \u03bc\u2080Ienlac\u00e9<\/label>\n<label><input type=\"radio\" name=\"m4\" value=\"0\"> \u222fB\u00b7dS = Q\/\u03b5\u2080<\/label>\n<label><input type=\"radio\" name=\"m4\" value=\"0\"> B = qv<\/label>\n<label><input type=\"radio\" name=\"m4\" value=\"0\"> \u222eE\u00b7dl = \u03bc\u2080I<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>5. Dans un sol\u00e9no\u00efde long id\u00e9al :<\/strong>\n<label><input type=\"radio\" name=\"m5\" value=\"1\"> B \u2248 \u03bc\u2080nI<\/label>\n<label><input type=\"radio\" name=\"m5\" value=\"0\"> B = 0 partout<\/label>\n<label><input type=\"radio\" name=\"m5\" value=\"0\"> B \u221d 1\/r\u00b2<\/label>\n<label><input type=\"radio\" name=\"m5\" value=\"0\"> B = qE<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>6. Si v est perpendiculaire \u00e0 B dans un champ uniforme :<\/strong>\n<label><input type=\"radio\" name=\"m6\" value=\"1\"> la trajectoire peut \u00eatre circulaire<\/label>\n<label><input type=\"radio\" name=\"m6\" value=\"0\"> la trajectoire est forc\u00e9ment rectiligne<\/label>\n<label><input type=\"radio\" name=\"m6\" value=\"0\"> la particule s&#8217;arr\u00eate<\/label>\n<label><input type=\"radio\" name=\"m6\" value=\"0\"> l&#8217;acc\u00e9l\u00e9ration est nulle<\/label>\n<\/div>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaMagScore()\">\nVALIDER MON QCM\n<\/button>\n\n<\/form>\n\n<div id=\"magResult\"><\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"cta\">\n\n<div style=\"font-size:43px\">\u222e B\u00b7dl = \u03bc\u2080I<\/div>\n\n<h2>En magn\u00e9tostatique, g\u00e9om\u00e9trie et sym\u00e9trie font gagner l&#8217;essentiel du temps.<\/h2>\n\n<p>\nCourants, direction du champ, r\u00e8gle de la main droite, Amp\u00e8re,\nforce de Lorentz et moment magn\u00e9tique constituent la base\nde tout le bloc \u00e9lectromagn\u00e9tisme \u00e0 venir.\n<\/p>\n\n<div class=\"actions\" style=\"justify-content:center\">\n<a href=\"#cours\" class=\"btn gold\">\ud83d\udcda REVOIR LE COURS<\/a>\n<a href=\"#exercices\" class=\"btn glass\">\ud83e\udde9 EXERCICES<\/a>\n<a href=\"#qcm\" class=\"btn glass\">\u2753 REFAIRE LE QCM<\/a>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<script>\nfunction mzaMagHint(id){\n const el=document.getElementById(id);\n if(!el)return;\n el.style.display = el.style.display===\"block\" ? \"none\" : \"block\";\n}\n\nfunction mzaMagScore(){\n const form=document.getElementById(\"magQuiz\");\n const result=document.getElementById(\"magResult\");\n\n let score=0;\n let complete=true;\n\n [\"m1\",\"m2\",\"m3\",\"m4\",\"m5\",\"m6\"].forEach(function(name){\n   const answer=form.querySelector('input[name=\"'+name+'\"]:checked');\n\n   if(!answer){\n     complete=false;\n   }else{\n     score+=Number(answer.value);\n   }\n });\n\n result.style.display=\"block\";\n\n if(!complete){\n   result.innerHTML=\"<strong>R\u00e9pondez aux 6 questions avant de valider.<\/strong>\";\n   return;\n }\n\n const pct=Math.round(score\/6*100);\n\n let level=\"Magn\u00e9tostatique \u00e0 consolider\";\n if(pct>=50) level=\"Fondations acquises\";\n if(pct>=67) level=\"Bon niveau\";\n if(pct>=84) level=\"Tr\u00e8s bonne ma\u00eetrise\";\n if(pct===100) level=\"Excellent niveau CPGE\";\n\n result.innerHTML=\n \"<strong style='font-size:30px;color:#efd68c'>\"+pct+\"%<\/strong>\"+\n \"<p><b>\"+level+\"<\/b><\/p>\"+\n \"<p>Score : \"+score+\" \/ 6<\/p>\"+\n \"<p>Les r\u00e9ponses correctes et la correction d\u00e9taill\u00e9e restent masqu\u00e9es.<\/p>\";\n}\n<\/script>\n\n<\/div>\n&#8220;`\n","protected":false},"excerpt":{"rendered":"<p>&#8220;`html COURS 08 \u2022 PHYSIQUE CPGE Courants.Champs. Trajectoires. La magn\u00e9tostatique d\u00e9crit les champs cr\u00e9\u00e9s par des courants stationnaires. Force de Lorentz, Biot-Savart, Amp\u00e8re, sol\u00e9no\u00efdes et moments magn\u00e9tiques forment un ensemble central de l&#8217;\u00e9lectromagn\u00e9tisme CPGE. \ud83d\udcda COMMENCER \ud83e\udde0 M\u00c9THODE \ud83e\udde9 EXERCICES \u2753 QCM 1. CHAMP MAGN\u00c9TIQUE Une grandeur vectorielle cr\u00e9\u00e9e notamment par les courants. Notation B [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1593","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages\/1593","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/comments?post=1593"}],"version-history":[{"count":1,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages\/1593\/revisions"}],"predecessor-version":[{"id":1595,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages\/1593\/revisions\/1595"}],"wp:attachment":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/media?parent=1593"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}