1、河北经贸大学成人教育毕业论文河北经贸大学继续教育学院 毕 业 论 文论文题目 浅析三国演义中魏国的谋臣形象 指导教师 专业 汉语言文学 班级 2014级 姓名 完成日期 2016年2月28日 摘 要三国演义作为我国四大名著之一,是我国第一部长篇章回小说,也是历史演义小说的开山之作。该书以描写战争为主,反映了魏、蜀、吴三个政治集团之间的政治和军事斗争。三国在发展历程中虽各有曲折,所占据的有利条件也大相径庭,但其核心竞争力却是一致的,那就是人才谋臣。三国演义中所展现的时代是一个“不唯君择臣,臣亦择君”的时代,以荀彧为首的魏国谋臣们作为一个整体,在曹操早期的发展以及之后关键性的官渡之战中表现了超凡的
2、才智,对曹操的功业做出了贡献。同样,对于赤壁之战的惨败,谋臣们也脱不开干系。本篇论文着重分析曹魏集团中谋臣们在发展历程中,所表现出的政治策略、军事指挥、计谋权术等方面的卓越能力,让我们看到了个人前途与国家发展之间的辩证关系。关键词 三国演义;谋臣;谋略;国家发展 IIAbstract The romance of the Three Kingdoms as one of Chinas four famous, is Chinas first full-length novels, is the historical novel Romance of mountains. This book i
3、s to describe the war mainly reflects the Wei, Shu and Wu three political groups of political and military struggle. Three Kingdoms in the course of development, although there are twists and turns, to occupy the favorable conditions are different, but the core competitiveness is the same, it is tal
4、ent adviser. Revealed in the romance of the Three Kingdoms era is a not only the king chose officials, Tomson also chose kings era, headed by Xun Yu Wei of the advisers as a whole, in the development of Cao Caos early and later the battle of Guandu key in the performance of the extraordinary wisdom,
5、 of Cao Caos power industry has contributed to. Similarly, the Chibi fiasco, advisers were also to blame. This thesis focuses on the analysis of Wei Group advisers in the course of development, the political strategy, military command, trick trickery and outstanding ability, let us see the dialectic
6、al relationship between personal future and national development.Keywords The romance of the Three Kingdoms;;policy makers; strategy;national developmentIII目 录 绪论1 一、谋臣群体的涌现与魏国崛起的关系1(一)谋臣群体助力魏国跻身强国行列1(二)谋臣在“官渡”之胜与“赤壁”之败中起到的作用2 二、曹魏政权的谋臣集团3(一)政治策略的不世之才荀 彧4(二)用兵若神的军事奇才司马懿5(三)机变诡异的权术大师贾 诩6 三、曹操与谋臣之间的利益
7、关系7 四、结论8 参考文献9IV浅析三国演义中魏国的谋臣形象绪论“方今天下大乱,智士劳心之时也”。三国演义中曹操对荀攸所说的这段话,准确地描写出了谋臣在三国期间所具有的时代地位。细数历史各朝各代,谋臣,作为一个特殊的群体,在重大事件的演变的过程中,起到了推波助澜的重要作用。三国演义中谋臣不仅多,而且奇,尤其是魏国的谋臣更是奇才云集,异能纷呈,令人目不暇接,真可谓“才谋个别,境界独殊,以迥异于千古。” 李国文:李国文新评三国演义,作家出版社,2006年版一、谋臣群体的涌现与魏国崛起的关系三国时代在中国历史上虽然只是惊鸿一瞥,但书中却详尽描述了各路诸侯群雄割据,逐鹿中原的宏伟场景。此外,罗贯中还
8、用了浓墨重彩刻画了诸多斗智斗勇、唇枪舌剑的场面。而引领这些大事件发生的导演,正是“运筹帷幄之中,决胜千里之外”的谋臣们。小说中,曹操集团中重要谋臣包括荀彧、荀攸、郭嘉、程昱、贾诩、刘晔、许攸等以及后期的司马氏等,这些人的家世、际遇各不相同,有主动投奔的,有被迫而来的,但都是促成曹操统一北方并为乱世的终结铺垫下基石的谋臣。 (一)谋臣群体助力魏国跻身强国行列三国演义中的谋臣与君主之间的关系是对立统一的关系,统一性表现在相依相求中求得共存,谋臣寻找的是自己理想中的能赏识自己的君主, 而君主寻求的是顺从自己的能力为此尽心尽责的谋臣 周仲强:唯才是举以德用才试论三国演义中曹操的用人艺术,黑河学报,20
9、06年版。在三国演义中动乱的年代,由于许多文士散布于四野,引荐、推介往往是比宣召、发榜更为有效和普遍的征召方式,一个人的发现和重用会产生滚雪球式的连锁反应。曹操集团的谋臣群在形成和发展上便是这种形式的典型。在三国演义的第十回,交代了这个谋臣群体的形成:荀彧看透袁绍难成大事,于是带着侄子荀攸离开袁绍,主动投奔曹操,并且举荐了程昱,而程昱又推荐了郭嘉,郭嘉又推荐了刘晔很快,这个以颍川士人为核心的谋臣群体以互相举荐的形式逐渐发展壮大,成为曹操手下不可或缺的智囊。曹操在政治、军事上能从小到大,不断发展 ,并逐个消灭其他割据势力,成为中原地区的实际君主,其中以荀彧为首的谋臣集团可谓居功至伟。建安元年,历
10、经百难的献帝终于从长安回到破落不堪的洛阳。此时的大汉王朝大厦将倾,汉天子困在洛阳窘得无饭可食,“汉末气运之衰,无甚于此。” 罗贯中:三国演义14回,中国戏剧出版社,2007年版此时,李傕、郭汜挟重兵以争于外,而杨奉、韩暹二心以争于内,献帝不得已带领百官往东逃避。此时又是谋臣及时向曹操献策说:“昔晋文公纳周襄王而诸侯从,汉高祖为义帝发丧而天下归心 。今天子蒙尘,将军因此时首倡义兵,奉天子以从众望,不世之略也。若不早图,人将先我而为之矣。”他要曹操效仿晋文公、汉高祖,以护驾勤王为名使天下归服,这就是人们常说的“挟天子以令诸侯”之术。曹操接受他的意见,率领二十万精兵前往洛阳,打败李傕、郭汜,又逼走杨
11、奉,后又接受董昭迁都许都的建议,从此朝廷、献帝都为曹操所控制,使他在政治上获得了极大的主动,为之后统一北方垫下了基石。 (二)谋臣在“官渡”之胜与“赤壁”之败中起到的作用官渡之战与赤壁之战可谓是三国时期的两大战役,同时也是事关魏国生死存亡,重振旗鼓的大事件。前者是曹操与袁绍两大政治、军事集团为争夺北方地区霸主地位的关键战役;后者是曹操在平定北方之后,挥师南下,统一全国的成败之战。前者曹操大胜,后者曹操大败,而胜败中都有谋臣在其中发挥了重要的作用。官渡之战,就势力对比来看,袁绍处于绝对优势,曹操处于绝对劣势,袁胜曹败,当是情理之中。可战争的实际结果却出乎人们的意料:袁绍不仅大败,而且被彻底歼灭;
12、曹操不仅大胜,而且完全控制了黄河以北地区。这其中,谋臣集团所发挥的作用可以说是决定性的。诸葛亮在隆中对中曾与刘备谈道:“曹操势不及袁绍,而竟能克绍者,非唯天时,抑亦人谋也。” 晋朝陈寿:三国志蜀志诸葛亮传在曹操与袁绍决战前昔,郭嘉进著名的“十胜十败”之说,打消了曹操的疑虑,坚定了曹操战胜袁绍的信心。然后又采纳郭嘉、荀彧之谋,专攻徐州的吕布,以除后顾之忧。袁、曹决战发生后先后有临阵投诚的许攸献乌巢烧粮之计、程昱献“十面埋伏”之计、许攸献水淹冀州之计、郭嘉进北征乌桓之计、郭嘉遗计定辽东。自此,官渡之战以曹操完胜而告终,此时曹操的势力可谓并世无双,在谋臣们的辅佐下,他终于有机会实现自己“扫清四海,削
13、平天下”的理想。赤壁之战中,曹操挟胜势而来,大军南指,刘琮束手,刘备一路败逃,继而陈兵长江北岸,威震江南。然而强大的曹军惨败,弱小的孙、刘联军大胜,除了再一次印证了“骄兵必败,哀兵必胜”的思想外,谋臣所发挥的功效也不可小觑。当时的曹营自上至下都弥漫着一种骄傲轻敌的气氛,连荀攸、程昱这样的谋臣也跟着失去理智,变得轻飘浮躁起来。这使得曹操及谋臣们的决策和指挥出现失误,在隆冬时节以长于陆战的北军与孙、刘联军水战,可以说是在错误的时间、错误的地点,用错误的方式打了一场本该打赢的战争。同时火烧赤壁的关键并非周瑜的反间计与诸葛亮的借东风,而是庞统所献于曹操的连环计以及徐庶的心系刘备,坐视不管才使火烧之计得
14、以实现。可以说,赤壁之战,曹操是败于谋略,无怪乎曹操在逃脱之后,“哭郭嘉之哭,所以愧众谋臣也” 朱一玄:三国演义资料汇编Z,南开大学出版社,2003年版,这正是谋臣在曹操赤壁之失中所体现的意义。二、曹魏政权的谋臣集团三国是个群雄争斗的大舞台,各路诸侯斗力斗智,展开激烈的争斗,而争斗的胜负关键所在就是人的争夺。在这一过程中,曹操无疑是个胜利者。在他身边聚集了三国时代许多最优秀的文武人才,成为他事业取胜的有力保证,究其主要原因在于他思贤若渴,重才爱才,而且知人善任。孙权更是对他的用人之道给予了高度评价:“至于御将,古之少有,比之于操,万不及也。”在曹操谋臣集团中,大致可以分为政治、军事、外交三大类
15、型谋臣,下面将对这三类谋臣中的代表人物进行深入剖析。 (一)政治策略的不世之才荀彧荀彧是曹魏集团中的政治策略大家,自小就被世人称作“王佐之才”,他在战略上为曹操制定并规划了统一北方的蓝图,政治方面为曹操举荐了荀攸、司马懿、郭嘉等大量人才。荀彧在建计,密谋,匡弼,举人多有建树,被曹操称为“吾之子房”。荀彧最突出的特点之一就是深谋远虑,每每做大事情必先考虑其后的发展。早年其投于袁绍门下,因知袁绍终不能成大事遂与其侄荀攸投奔曹操。曹操在政治上、军事上由一个一般的割据武装成为北方的实际统治者,确立了最后三足鼎立的历史格局,可以说多半归功于荀彧的谋略。最能体现这点的是荀彧为曹操所做的三大决策,即建立稳定
16、的根据地,迎汉献帝于许都,与袁绍进行官渡之战。曹操在占据兖州为根据地之后,为其父死于陶谦部下之手而耿耿于怀,举大军攻打徐州。曹操攻打陶谦时吕布袭取了兖州,荀彧临危不惧,单身前往说退豫州刺史郭贡的数万人马,并与程昱保住了三座城池,巩固了曹操的大后方。当听到陶谦病死,刘备做了徐州牧后,曹操又要起兵讨伐刘备。在这个关键时刻,荀彧谏曰:“今陶谦虽死,已有刘备守之。徐州之民,既已服备,必助备死战。明公弃兖州而取徐州,是弃大而就小,去本而求末,以安而易危也。”从这段谏词中可以看出荀彧目光长远,工于谋略。而后荀彧劝曹操迎汉献帝于许都,挟天子以令诸侯,从而致使曹操在之后很长的一段时间内都能以中央的名义进行征伐
17、,在政治上掌握了主动权,为其讨伐诸侯的胜利奠定了一定的基础。官渡之战前,曹操因为军力与粮草不济,萌生退兵避袁绍之锋锐的想法。正当犹豫不决之际,荀彧至书曹操提出:“公以至弱当至强,若不能制,必为所乘;是天下之大机也。”“公今划地而守,扼其喉而使不能进,情见势竭,必将有变。此用奇之时,断不可失。”从而彻底稳定了曹操的开战之决心,于是有了官渡之战的胜利,基本统一北方。小说中荀彧尽管很少跟随曹操出现在战争第一线,却知运筹帷幄而决胜千里之外,不得不让人钦佩。 (二)用兵若神的军事奇才司马懿司马懿是继曹操之后,魏国唯一在军事谋略方面能与诸葛亮抗衡的人,其军事思想和曹操基本一致,以破蜀为主线,所以曹操临终前
18、,征召曹洪、陈群、贾诩、司马懿等同至病榻前,嘱以后事。曹操清楚地明白,只有司马懿能忠实地贯彻、执行和延续自己的政治、军事路线,他能够紧紧抓住魏蜀这对主要矛盾下功夫,有效地帮助曹氏打拼天下、巩固政权。司马懿具有长远的军事谋略目光,他极会从作战实践中寻思、总结敌方的作战规律和经验等以知己知彼。如97回曹休被东吴陆逊大破于石亭,气忧成疾而亡,司马懿旋即引兵回朝。众将笑他心怀畏惧,他只好道明实质缘由:“诸葛亮知吾兵败,必乘虚来取长安。”能科学预见事物发展趋势而做好应变工作,有备无患,司马懿之才果不可小觑。又98回司马懿推算出蜀兵行粮只有一月,利在急战,而曹军只宜久守,所以他请求曹叡降诏,命曹真“坚守各
19、路关隘不要出战,不须一月,蜀兵自走”,然后再俟时机乘虚击之。行军作战拼得不仅仅是精锐的作战力,还有粮草、车马等物质供给力量,如果不懂得实力对比,硬碰硬,那只能造成无谓的牺牲。司马懿擅于利用各种综合条件,多方瞄准敌人的软肋,使之无暇顾及。后来曹叡问司马懿既有先见之明,为何不自引一军而袭之?司马懿坦然答:“臣非惜身重命,实欲存下此兵,以防东吴陆逊耳。孙权不久必将僭号称尊,如称尊号,恐陛下伐之,定先入寇也,臣故欲以兵待之。”能预见到事物发展的一步,是明智;能看到两步,是聪明;能看到三步甚至更远,则是高明。当司马懿闲居宛城时,魏国在军事上面临屡屡失利的困境,曹叡不得不再次起用司马懿。司马懿本应统领本部
20、军马先赶到都城觐见圣上,可在接到孟达欲反的密报后,司马懿大惊,“若旦夕不用吾时,孟达一举,两京破矣”,遂果断地先斩后奏,即刻领军一日行二日之路,一面传令孟达准备征进,使其不疑。待司马懿星夜兼程赶到新城,出其不意攻其不备,孟达只得乖乖就擒,魏国危急之势得以解除。若事前司马懿循规蹈矩地依条令先上奏表,等到皇帝批准后再行动,那时异则势异,两京形势定然告急。正是由于司马懿的灵活多变,适时而动,才力挽狂澜,保障了魏国的安全。司马懿之所以能蛰伏多时却出师大捷,就是因为他在时刻准备战斗着,在看似偶然性的背后隐含着绝对的必然性。 (三)机变诡异的权术大师贾诩三国演义小说中,谋臣逞雄,英才齐出。“唯有贾诩是一个
21、不可等闲视之德人物,也是这部书里唯一大获全胜,最终立于不败之地的大谋臣。诸葛亮,应该说是最光辉的典型,但他并不是最成功的。出师未捷身先死,便是最大的遗憾。” 李国文:李国文新评三国演义,作家出版社,2006年版贾诩其人奇谋百出,三国志说他“算无遗策,经达权变” 晋陈寿:三国志魏志荀彧攸贾诩传。贾诩是一个头脑清醒,且善于计谋权术明哲保身的谋臣。董卓死后,部将李傕和郭汜率军逃离,遇见贾诩,贾诩劝其杀奔回京,挟持皇帝。因此有人说三国的战乱,是由贾诩的一句话惹来的,这固然夸大了他的作用,事态的发展是受各方面因此融合发生的,没有李傕郭汜,还有另外的军军阀犯上作乱也不一定。后来李傕郭汜和曹操对军,贾诩劝其
22、降曹,险些被杀。后辗转成为张绣谋臣,张绣多次用贾诩之计谋打败曹操,折其大将典韦和长子曹昂,显示出了贾诩非凡的大智谋。而他喜爱投靠那些无谋又听他计策之辈,也许正因为如此,他才能充分展示他的个人才华。贾诩的卓越见识和深谋远见给曹操留下了很深影响。官渡之战前贾诩投降曹操,被封为都亭侯。贾诩怕曹操妒其才,便很少结交权势,也很少献策,除非曹操问及。后来贾诩在破潼关马超和战袁绍等战中屡献奇策。赤壁之战时曾劝曹操切勿南下,曹操不听,以致赤壁大败。后来曹操欲立世子,多次问于贾诩,贾诩此时站在了曹丕这一派,便以袁绍和刘表为例,使曹操下定了立曹丕为世子的决心。曹丕即位后,封贾诩为太尉,位列三公。贾诩的低调从政,明
23、哲保身,从不攀附权贵,周泽雄先生他的三国人物评中称其为“乱武”。能在汉末乱世中四处奔投却又寿终正寝的,贾诩是唯一的一位了。 三、曹操与谋臣之间的利益关系 纵观人类几千年的发展史,无论是古今中外还是本士异域,我们都可以看到这样一个反复出现的社会现象,即“人才聚,事业兴,人才散,国家亡”。“得人才者得天下,失人才者失天下”,这是不言而喻的历史规律。曹操是三国时期的政治家、军事家,他在统一北方的过程中体现了作为一个杰出人物所具备的素质。他不仅充分施展他的聪明才智和雄才大略,而且还能充分利用他周围的贤臣谋臣为他的统一大业服务。在各类戏曲作品中,人们常鄙夷曹操为“奸雄”,而在三国演义中,他的谋臣们则更多
24、地佩服他的雄才伟略,承认他的权威王道,更折服他的人格力量:其“奸”的一面令人生畏,其“雄”的一面令人敬仰乃至崇拜 陈继征:论曹操的“奸”与“雄”,西安交通大学学报,2000年版。谋臣们相信跟随他能创功立业,列土封侯,荣华富贵,名垂青史,所以心甘情愿地为他效命。他们分别以共同的目的, 及择主思想走到一起, 成为推动曹魏集团前进的能量之源。然而,君臣之间的关系并非毫无缝隙,同样存在统一对立的两面性。统一方面表现在“臣”所遵循的宗法观念及思想精髓与君权政治相统一。“臣”的价值观必须为君权王道所认可,而君权政治的权威性、合法性又必须接受“臣”的仲裁与承认。只有两者的统一,才能推动社会的发展确保社会安定
25、。对立方面:谋臣们在认可君权的同时,又想对君权进行约束,在他们的心里深处遵循的是“道”尊于“势” 王志武:中的曹操是如何对待人才的,唐都学刊,2003年版。作为谋臣阶层的他们遵奉的行为规范则是自身尊严的强悍人生。尽管大一统的政治不断造就对君权政治的迎合与谄媚,但从整体上来看,谋臣们大都有着宽广胸襟和以天下为己任的济世情怀,以不卑不亢的态度去为官处事,这也就造成君臣之间不可调和的矛盾。这也恰恰体现出了谋臣们政治伦理的选择和功利选择的结合,择主而事和为主尽忠的结合。 四、结论所谓三国能在群雄混战中割据一方,各有立国之本,魏占天时,吴占地利,蜀占人和。其实,得天下的战略表面看来有天时地利人和各种因素
26、,说穿了只有一条:人才。随着群雄的逐鹿中原,谋臣大量涌现,可以说达到了鼎盛的时期。三国演义的作者罗贯中在反映这段历史的同时,并没有忽略在当时起了重大作用的谋臣。他们在一系列重要事件中所表现出来的才能以及运用这些 能力发挥的参谋与决策作用。无怪乎清朝史学家赵翼说道:“人才莫盛于三国,亦惟三国之主各能用人,故得众人相扶,以成鼎足之势,而其用人亦各有不同者,大概曹操以权术相驭,刘备以性情相契,孙氏兄弟以意气相投” 赵翼,廿二史札记,中华书局, 。此书在今天读来,仍然有着欲罢不能的诱惑力。参考文献1 李国文:李国文新评三国演义,作家出版社,2006年版。2 周仲强:唯才是举以德用才试论三国演义中曹操的
27、用人艺术,黑河学报,2006年版3 罗贯中:三国演义14回,中国戏剧出版社,2007年版。4 晋朝陈寿:三国志蜀志诸葛亮传。5 朱一玄:三国演义资料汇编Z,南开大学出版社,2003年版。6 李国文:李国文新评三国演义,作家出版社,2006年版。7 晋陈寿:三国志魏志荀彧攸贾诩传。8 陈继征:论曹操的“奸”与“雄”,西安交通大学学报,2000年版。9 王志武:中的曹操是如何对待人才的,唐都学刊,2003年版。10 赵翼:廿二史札记,中华书局,2001年版。请删除以下内容,O(_)O谢谢!conduction, transfer of heat or electricity through a s
28、ubstance, resulting from a difference in temperature between different parts of the substance, in the case of heat, or from a difference in electric potential, in the case of electricity. Since heat is energy associated with the motions of the particles making up the substance, it is transferred by
29、such motions, shifting from regions of higher temperature, where the particles are more energetic, to regions of lower temperature. The rate of heat flow between two regions is proportional to the temperature difference between them and the heat conductivity of the substance. In solids, the molecule
30、s themselves are bound and contribute to conduction of heat mainly by vibrating against neighboring molecules; a more important mechanism, however, is the migration of energetic free electrons through the solid. Metals, which have a high free-electron density, are good conductors of heat, while nonm
31、etals, such as wood or glass, have few free electrons and do not conduct as well. Especially poor conductors, such as asbestos, have been used as insulators to impede heat flow (see insulation). Liquids and gases have their molecules farther apart and are generally poor conductors of heat. Conductio
32、n of electricity consists of the flow of charges as a result of an electromotive force, or potential difference. The rate of flow, i.e., the electric current, is proportional to the potential difference and to the electrical conductivity of the substance, which in turn depends on the nature of the s
33、ubstance, its cross-sectional area, and its temperature. In solids, electric current consists of a flow of electrons; as in the case of heat conduction, metals are better conductors of electricity because of their greater free-electron density, while nonmetals, such as rubber, are poor conductors an
34、d may be used as electrical insulators, or dielectrics. Increasing the cross-sectional area of a given conductor will increase the current because more electrons will be available for conduction. Increasing the temperature will inhibit conduction in a metal because the increased thermal motions of t
35、he electrons will tend to interfere with their regular flow in an electric current; in a nonmetal, however, an increase in temperature improves conduction because it frees more electrons. In liquids and gases, current consists not only in the flow of electrons but also in that of ions. A highly ioni
36、zed liquid solution, e.g., saltwater, is a good conductor. Gases at high temperatures tend to become ionized and thus become good conductors (see plasma), although at ordinary temperatures they tend to be poor conductors. See electrochemistry; electrolysis; superconductivity. Almost everyone has exp
37、erienced the Doppler effect, though perhaps without knowing what causes it. For example, if one is standing on a street corner and an ambulance approaches with its siren blaring, the sound of the siren steadily gains in pitch as it comes closer. Then, as it passes, the pitch suddenly lowers percepti
38、bly. This is an example of the Doppler effect: the change in the observed frequency of a wave when the source of the wave is moving with respect to the observer. The Doppler effect, which occurs both in sound and electromagnetic wavesincluding light waveshas a number of applications. Astronomers use
39、 it, for instance, to gauge the movement of stars relative to Earth. Closer to home, principles relating to the Doppler effect find application in radar technology. Doppler radar provides information concerning weather patterns, but some people experience it in a less pleasant way: when a police off
40、icer uses it to measure their driving speed before writing a ticket. Sound and light are both examples of energy, and both are carried on waves. Wave motion is a type of harmonic motion that carries energy from one place to another without actually moving any matter. It is related to oscillation, a
41、type of harmonic motion in one or more dimensions. Oscillation involves no net movement, only movement in place; yet individual points in the wave medium are oscillating even as the overall wave pattern moves. The term periodic motion, or movement repeated at regular intervals called periods, descri
42、bes the behavior of periodic waveswaves in which a uniform series of crests and troughs follow each other in regular succession. A period (represented by the symbol T ) is the amount of time required to complete one full cycle of the wave, from trough to crest and back to trough. Period is mathemati
43、cally related to several other aspects of wave motion, including wave speed, frequency, and wavelength. Frequency (abbreviated f ) is the number of waves passing through a given point during the interval of one second. It is measured in Hertz (Hz), named after nineteenth-century German physicist Hei
44、nrich Rudolf Hertz (1857-1894), and a Hertz is equal to one cycle of oscillation per second. Higher frequencies are expressed in terms of kilohertz (kHz; 103 or 1,000 cycles per second); megahertz (MHz; 106 or 1 million cycles per second); and gigahertz (GHz; 109 or 1 billion cycles per second.) Wav
45、elength (represented by the symbol , the Greek letter lambda) is the distance between a crest and the adjacent crest, or a trough and an adjacent trough, of a wave. The higher the frequency, the shorter the wavelength. Amplitude, though mathematically independent from the parameters discussed, is cr
46、itical to the understanding of sound. Defined as the maximum displacement of a vibrating material, amplitude is the size of a wave. The greater the amplitude, the greater the energy the wave contains: amplitude indicates intensity, which, in the case of sound waves, is manifested as what people comm
47、only call volume. Similarly, the amplitude of a light wave determines the intensity of the light. electromagnetic radiation,energy radiated in the form of a wave as a result of the motion of electric charges. A moving charge gives rise to a magnetic field, and if the motion is changing (accelerated), then the magnetic field varies and in turn produces an electric field. These interacting electric and magnetic fields are at right angles to one another and also to the direction of propagation of the energy. Thus, an electromagnetic wave is