2014年电磁场与电磁波期末复习?- 百度文库 ر

2д㶨ųеİ໷·ɲ˵ųǷΪس 𣺺㶨ųеİ໷·Ϊ

C?H?dl??J?dSS˹п˹ɵ

C?H?dl????H?dS??J?dS??H?JΪ㣬ʲDZس

SS3ζģд˫ݵĻ衣

𣺵ǵϵͳһֻԣϵͳĵݶΪqλ? ıֵŵɣ?qĵɵĵΪq֮ĵѹU֮ȡ

ĵΪ

C?q?

˫ĵݶΪ

C?

q U˫IJΪ

ٸݵļ״ѡȡʵϵ ڼٶϷֱ+q-q ۸ݼٶĵE ;

U?C??E?dlѹ;

12qC. U4̬ΩһԶҪ˵Ҫ塣 𣺾̬ΩһԶڳV ı߽Sϸ?V Ωһֵ

ΩһԶҪ壺˾ֵ̬ΩһΪֵ̬ĸⷽṩݣΪȷṩоݡ

5ʲôǾ񷨣ʲôȷɵķֲ

ʵλϣĵɵЧֲӵĵɵķΪ񷨡񷨵ΨһԶ

񷨵ԭΪеľɱλ֮ĿռУھɵĸλüĴСԭ߽ȷ

??ֵɷ̻˹?n

6ֱд˹ΤĻʽ΢ʽҪ˵ 𣺻ʽ

һ˵ųǿպߵĻڴԸ

??D?dS??CH?dl??SJ?dS??Sڶ˵糡ǿպߵĻڴԸ?t???E?dl???B?dS պΪܽĴͨ仯ʵĸֵ ?S?t??C?˵պĴŸӦǿȵͨ0 ??SB?dS?0?ķ˵պĵλƵͨڸñպ??D?dS???dVV?SɵɵĴ͡

΢ʽ

պΪܽĴλƵ֮͡

??D???H?J??t?????E???B ??t????B?0?????D??һ̶԰໷·仯ĵ糡ǴųԴ

ڶΪŸӦɣ˵仯Ĵų糡 ˵ųΪɢ ķ˵Ϊ糡Դ

7дӡ͢ĻʽҪ˵塣 ӡ͢ĻʽΪ

?d????1??1????(E?H)?dS??(E?D?H?B)dV??E?JdV SVdtV22壺λʱڣͨS VĵV ӵĵųĵ֮͡ӡ͢DZغϵĶ

d1??1??(E?D?H?B)dV λʱV ӵĵ ?Vdt22??E??JdVʱڵ糡VеĵĹڵýУΪVܵĹ

??S???(E?H)?dS ͨS V ĵŹʡ

8ʲôDzļ˵༰жϹ

𣺵Ųļָڿռ㴦糡ʸĶ˵ʱ仯Ĺ켣Ϊ߼ԲԲࡣ

Ųļ״̬ȡEx Ey ExmEymλ?գyx+ z 򴫲ľƽ沨

߼ ? = 0? ? = 013ޣ? = ? 24ޣ ԲExm = Eym? = ? /2ȡԲȡԲ Բ? 0? 0 9ֱ˵ƽ沨СýеĴԡ 𣺾ƽ沨еĴԣ

ٵ糡ų봫֮໥ֱǺŲ ڵ糡ų˥ ۲迹Ϊʵ糡ųͬλ ܵŲƵ޹أɫɢ ƽųܶȵƽ糡ܶȡ ƽ沨ڵýеĴԣ

ٵ糡ų봫֮໥ֱǺŲ ڵ糡ųָ˥ ۲迹Ϊ糡ųͬλ ܵŲƵйأɫɢ ƽųܶȴƽ糡ܶȡ 10Ҫ˵вפפ֮

вIJϵ??0פϵS?1פ㣨פ㣩ڿռûƶֻԭλ񶯣ϵ|?|?1פϵS??פֵͲΪСֵ֮仯ϵ0?|?|?1פϵ1?S?? 11Ҫ˵żԶԡ 𣺵żԶԣ

ԶǺŲ糡ųʹ໥ֱ Զ糡ųȵýʵı迹 ԶǷǾ沨ų1/r ȣ Զзԣ sinȱ仯

??a??1?0?1糡һ뾶ΪaԲ壬֪ԲڡĵλΪ?a2??2?A(???)cos??Բڡĵ糡ǿȣܶȡ ʾ ?u?e???a

??u??u??u ?e??ez??????z⣺Բڵĵ糡ǿΪ

E1????1?0

Բĵ糡ǿΪ

????2???2???2?E2????2????e????e?????ez?z????

22??a?a?????e?A?1?cos??eA1????2???2??sin?????ܶΪ

?S?en?D2?D1????a?e???0E2????a??2Acos?

2 ͬεڵ뾶Ϊa⵼뾶Ϊb糣ΪŵľȽʡ֪ڵЯq󣺢ٽڵĵ糡ǿE ڸεĵݡ

⣺ ˹

???D?dS?q,D???qq,E?er(3) 224?r4??r ⵼ѹ

U??Edr?ab11qb?a(?)?? 4??ab4??abqɵݵĶC?qõ UC?q4??ab? Ub?a3 һŵΪ ̰뾶Ϊa ޳ȵԲ߷ǿΪ IԲ

ŸӦǿBʹųǿH