大学物理简明教程课后习题及答案 - 百度文库 ر

?I1B1?ֽ

?I(2???)B1?01

2R2??I2B2?ֽ

?0I2?

2R2?BI(2???)?1 1?1B2I2?B2???? B0?B1?B2?0

6-7 6-7ͼеĵΪ8Aͼʾպa,b,cֱд໷·ʽұߵĴۣͣ

(1)ڸպϣĴŸӦǿBĴСǷ? (2)ڱպcϸBǷΪ?Ϊʲô?

????⣺ ?B?dl?8?0

a???dl?8?0 ?baB??B?dl?0 ?c?(1)ڸպϣBĴСȣ

???(2)ڱպCϸBΪ㣮ֻBĻ·ΪÿB?0

6-7ͼ

6-8 һܳͬ£һԲ(뾶Ϊa)һͬĵԲ(ڡ뾶ֱ Ϊb,c)ɣ6-8ͼʾʹʱIһȥһأǾȵطֲڵĺϣ(1)Բ(ra),(2)֮(arb)3ԲͲ(brc)Լ(4)(rc)㴦ŸӦǿȵĴС ⣺

?L??B?dl??0?I

Ir2(1)r?a B2?r??02

RB?(2) a?r?b B2?r??0I

?0Ir 2?R2?0I 2?rB?r2?b2??0I (3)b?r?c B2?r???0I2c?b2?0I(c2?r2) B?222?r(c?b)(4)r?c B2?r?0

B?0

ѡ

6-8ͼ 6-9ͼ

?6-9 ڴŸӦǿΪBľȴųУֱڴųƽһߣΪI6-9ͼʾܵİ

?

⣺ȡdl

???b Fab??Idl?B

a?????? dlBн?dlB??䣬BǾȵģ

2????bb? Fab??Idl?B?I(?dl)?B?Iab?B

aaabϣСFab?BIab

6-10ͼ

6-10 6-10ͼʾڳֱABͨԵI1=20AھȦCDEFͨеI2=10 AABȦ棬CDEFABƽУ֪a=9.0cm,b=20.0cm,d=1.0 cm

(1)ABĴųԾȦÿõ (2)Ȧܺͺأ

? ⣺(1)FCDֱCD󣬴С

FCD?I2b?ͬFFEֱFEңС

FFE?I2b?FCFֱCFϣСΪ

?0I1?8.0?10?4 N 2?d?0I1?8.0?10?5 N

2?(d?a)?FEDֱED£СΪ

FED?FCF?9.2?10?5N

?????(2)F?FCD?FFE?FCF?FED󣬴СΪ

M?Pm?B Ȧ뵼߹

ѡ

FCF??d?ad?0I1I2?IId?adr?012ln?9.2?10?5 N 2?r2?d???F?7.2?10?4N

Pm//B

???M?0

6-11 һȦϸɣ߳ΪaNѣͨе

?һֱתȦͨеIȦھȵˮƽųBУȦתתΪJ.Ȧƽλ΢СʱT.

??⣺΢ʱȦ񶯽ǶΪ? (???Pm,B?)

M?PmBsin??NIa2Bsin?

d2?22ת J2??NIaBsin???NIaB?

atd2?NIa2B??0 2?JdtNIa2B 񶯽Ƶ ??

J2?J?2? T? ?Na2IB6-12 һֱͨеI120AԱ߷һabͨеI2=10A߹棬6-12ͼʾabOأ ⣺abȡdr ?dF?abϣСΪ

?IdF?I2dr01

2?r????dFOdM?r?F ?dMֱֽ⣬СΪ

?IIdM?rdF?012dr

2?b?IIbM??dM?012?dr?3.6?10?6 N?m

a2?a 6-12ͼ

?6-13 B=7010TǿųԲ˶Բܰ뾶r=3.0cm֪Bֱ

?ֽ⣬ijʱ̵A㣬ٶvϣ6-13ͼ

-4

(1)Ի˶Ĺ

?(2)ٶvĴС (3)ӵĶEk

ѡ

6-13ͼ

⣺(1)켣ͼ

v2(2) evB?m

reBr v??3.7?107m?s?1

m1(3) EK?mv2?6.2?10?16 J

2

6-14ͼ

6-14 6-14ͼе߱ʾֲͬŽʵB?HϵߣB=?0HϵߣָһDZʾ˳?һDZʾ?һDZʾ? : ߢ˳ʣߢǿʣߢʣ

6-15 ƻܳL=10cmȦN=200ѣȦͨеI=100 mA

??(1)ʱĵĴųǿHʹŸӦǿB0

??(2)ڳԴŵ?r=4200ĴʣڵBHǶ?

??*(3)ĴɵдB0ɴŻBǶ?

??: (1) ?H?dl??I

lHL?NI

NIH??200A?m?1

LB0??0H?2.5?10?4T

B??H??r?oH?1.05 T ??4(3)ɴB0(1)еB0?2.5?10T

(2)H?200 A?mɴŻB??B?B0?1.05

?1T

ϰ

7-1 һ뾶r=10cm뾶Ժ㶨

Բλ·B=0.8TľȴųУ·ƽBֱ·

?dr-1

=80cmsʱ·иӦ綯ƵĴС dt2: ·ͨ ?m?BS?Br

Ӧ綯ƴС

??d?mddr?(Br2)?B2r?0.40 V dtdtdtѡ