專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件

兩類典型問(wèn)題1.帶電粒子在有界勻強(qiáng)磁場(chǎng)中(只受洛倫茲力)做圓弧運(yùn)動(dòng);2.帶電粒子在磁場(chǎng)中運(yùn)動(dòng)時(shí)的臨界問(wèn)題(或多解問(wèn)題)的討論兩類典型問(wèn)題1概述1、本類問(wèn)題對(duì)知識(shí)考查全面,涉及到力學(xué)、電學(xué)、磁學(xué)等高中物理的主千知識(shí),對(duì)學(xué)生的空間想象能力、分析綜合能力、應(yīng)用數(shù)學(xué)知識(shí)解決物理問(wèn)題能力有較高的要求,是考查學(xué)生多項(xiàng)能力的極好的載體,因此成為歷年高考的熱點(diǎn)?！?、從試題的難度上看,多屬于中等難度或較難的計(jì)算題。原因有二:一是題日較長(zhǎng),常以科學(xué)技術(shù)的具體問(wèn)題為背景,從實(shí)際問(wèn)題中獲取、處理信息,把實(shí)際問(wèn)題轉(zhuǎn)化成物理問(wèn)題。二是涉及數(shù)學(xué)知識(shí)較多(特別是幾何知識(shí))概述2·3、常見(jiàn)的五種有界磁場(chǎng):單邊界磁場(chǎng)、雙邊界磁場(chǎng)、矩形磁場(chǎng)、圓形磁場(chǎng)、三角形磁場(chǎng)4、解題關(guān)鍵有三點(diǎn)①粒子圓軌跡的圓心O的確定②運(yùn)動(dòng)半徑R的確定③運(yùn)動(dòng)周期T的確定·3、常見(jiàn)的五種有界磁場(chǎng):單邊界磁場(chǎng)、雙3◆帶電粒子在勻強(qiáng)磁場(chǎng)中的運(yùn)動(dòng)由洛論力提供甸心力qB=m2軌道半徑:rnygB周期T與R和v無(wú)關(guān)僅由粒子種奏(m、q)運(yùn)動(dòng)周期:7=2zr2兀m決定,和感應(yīng)強(qiáng)度BqB決定。B角速度:O頻率:f==T2丌m動(dòng)能:E,=1my2=(qBR◆帶電粒子在勻強(qiáng)磁場(chǎng)中的運(yùn)動(dòng)4◆解題的基本過(guò)程與方法1找圓心6已知任意兩點(diǎn)速度方向:作垂線X可找到兩條半徑,其交點(diǎn)是圓心。已知一點(diǎn)速度方向和另外一點(diǎn)的+∞+位置:作速度的垂線得半徑,連接兩點(diǎn)并作中垂線,交點(diǎn)是圓心。x*、xxx2畫(huà)圓弧3定半徑:·幾何法求半徑公式求半徑4算時(shí)間:先算周期,再用圓心角算時(shí)間n2m1=2z[注意:θ應(yīng)以弧度制表示6=2aB◆解題的基本過(guò)程與方法5專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件6專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件7專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件8專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件9專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件10專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件11專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件12專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件13專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件14專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件15專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件16專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件17專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件18專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件19專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件20專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件21專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件22專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件23專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件24專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件25專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件26專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件27專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件28專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件29專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件30專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件31專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件32專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件33專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件34專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件35專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件36專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件37專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件38專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件39專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件40專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件41專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件42專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件43專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件44專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件45專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件46專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件47專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件48專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件49專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件50專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件51專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件52專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件53專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件54專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件55專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件56專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件57專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件58專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件59專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件60專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件61專題帶電粒子在有界磁場(chǎng)中運(yùn)動(dòng)和臨界問(wèn)題文課件62專題帶電粒子在有界磁場(chǎng)中運(yùn)