1、This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr oco
2、ntroler and DS18B20 t emperature sensor. 第六章 静 电 场 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The c
3、ore component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 主要内容 1.库仑定律 静电场力叠加原理 2.电场强度 3.高斯定理 4.电势 5.静电场中的导体 6.电容器的电容 7.静电场中的电介质 8.电容器的储能公式 相对于观察者静止的电荷所激发的电场 -静电场 掌握两个物理量 电场强度、电势及其计算；两者关系； 两个定理：高斯定理、环路定理 及导体和电介质的静电特性 This paper mainly int roduces the design of an int
4、eligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 两种电荷 正电荷和
5、负电荷 电性力 同号相斥、异号相吸 2.电荷量子化 e为电子电量 ,3,2,1 nneq1.电荷 宏观带电体的带电量 qe，准连续 库仑定律 静电力叠加原理 6.1 6.1.1 电荷 电荷量 物体带电的多少 ( , )qQThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temp
6、erature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 夸克模型理论预言 ,夸克带有 或 的电量 ,以四味 夸克为例 13 e 23 e3、电荷守恒定律 在一个与外界没有电荷交换的系统内，正负电量代数和在任何物理过程中保持不变。 夸克 带电 量 U quark (上 ) 2/3 |e| D quark(下 ) -1/3 |e| S quark(奇 )
7、 -1/3 |e| C quark(粲 ) 2/3 |e| This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of th
8、e system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 4、电荷相对论不变性 系统所带电荷量与参考系的选择无关 . + 电量为 Q x 电量为 Q x This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit
9、 al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 1 点电荷 Q d r 观察点 P 点电荷 -理想化的物理模型 2 库仑定律 在真空中，两个静止点电荷之间相互作用力与这两个点电荷的电荷量 和 的乘积成正比，与这两个点电荷之间的距离 （或 ）的平方成反比，作用力的方向沿着这两个点电荷的连线，同号相斥，异号相吸。 1q 2q12r
10、 21r6.1.2 库仑定律 可以简化为点电荷的条件 : dr121 2 ,1 2212rqqF k erThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The
11、 core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 121 2 ,1 2212rqqF k er 电荷 q1 作用于电荷 q2 的力。 12F12r q1 指向 q2 的矢量 ,12 12rer的单位矢量 说明 (1) q2对 q1的作用力 1221 ,21 12221rqqF k e Fr 两个静止点电荷之间的相互作用力符合牛顿第三定律 . (2)q1和 q2同性， 和 同向，为斥力 12F ,12req1和 q2异性， , 和 反向，为引力 12F ,1
12、2re12r1q 2q,12re12FThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar
13、 e AT89C51 micr ocontroler and DS18B20 t emperature sensor. （ 3） 单位制有理化 距离平方反比关系的实验验证 电摆实验装置 扭秤 卡文迪许同心球实验草图 014 k 121 2 ,1 220 1 214 rqqFer真空介电常量 或 真空电容率 12 2 20 8.85 10 C / N m This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper
14、 at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 0,031 0014nirii iqqFer两个点电荷之间的作用力不因第三个点电荷的存在而有所改变 q0 F 两个以上的点电荷对一个点电荷作用力等于各个点电荷单独
15、存在时对该点荷的作用力的矢量和 . q1 F1 10rq2 F2 20r6.1.3 静电力叠加原理 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The co
16、re component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 例在直角坐标系的原点 (0,0)、 x轴上的 （ 0.52,0)点和 y轴上的（ 0,0.3)点处 （ 单位为 m)分别放置 q1=50C， q2=-86C, q3=65C。 各电荷间的距离如图所示 。 求作用在 q3上合力的大小和方向 。 解 2 2 20.3 0.52 0.6 55913 25 .0 1 0 6 .5 1 09 .0 1 0 N0 .33 2 5 NF 13Fy3q0.3moj1q0.6mxi3
17、F23F2q0.52m13 325 NFj 55923 28 .6 1 0 6 .5 1 09 .0 1 0 N0 .61 4 0 NF This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip mic
18、rocom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 电场 23 23 23 23 23cos sinxyF Fi F j F i F j 121 70 Nij 3 13 23 13 23 13 23x x y yF F F F F i F F j (121 255)i jN223 282.3NxyF F F 与 x轴夹角 64.6o23 140NF 255ta n121yxFF y13F3q0.3moj1q0.6mxi3F23F
19、2q0.52m030 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C
20、51 micr ocontroler and DS18B20 t emperature sensor. 电荷之间的相互作用方式的两种观点 电场 电荷 1 电荷 2 超距作用 作用 作用 电荷 1 电荷 2 电场 1 电场 2 无须物质传递，作用速度无穷大，瞬间即达 必须由物质 (电场 )传递，以有限速度传递。 电场强度 6.2 6.2.1 电场 场是物质存在的形式 有质量、能量、动量 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the fu
21、nction of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 1 试验电荷 q0 q0足够小，对待测电场影响小 2 电场强度 0FEqAFq0 q0 BFAB电场中某点的电场强度等于单位正电荷
22、在该点所受的电场力。 点电荷 (尺寸小 ) 在不同点 ,q0受力的大小和方向一般不同 电场强度 某一定点则有 0/Fq为常矢量 6.2.2 电场强度 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single ch
23、ip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. (1)电场强度是电场的属性 ,与试探电荷无关 . (2)当 ,与 同向 0 0q F当 ,与 反向 0 0q FF qE(3)可由 求力 6.2.3 电场强度的计算 说明 1.点电荷的电场强度 3.连续分布电荷的电场强度 2.电场强度叠加原理和点电荷系的场强 This paper mainly int roduces the design of an intelig
24、ent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 2014 0rqqFerE
25、0qF2014 rq erEF0q1.点电荷的电场强度 (1) 讨论 场点 源点 rq re)( 0q Pre Er0,q 与 方向一致 ( )rrere)( 0q PEr 0,q 与 方向相反 ( )rreThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature
26、 sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. (2) ,0rE ，点电荷模型不成立。 0,rE qi q2 q0 q1 1F2FiF1niiEE 2.电场强度叠加原理和点电荷系的场强 0qFE 021qFFF n nEEE 21nFFFF 21 ni iF1 点电荷系在空间任一点的总电场强度等于各个点电荷单独存在时在该点激发的电场强度的矢量和 场强叠加原
27、理 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr o
28、controler and DS18B20 t emperature sensor. 点电荷系的电场强度 21 014 nirii iqEer q2 - 2r2EE场点 q1 + 1E1rThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS
29、18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 3.电荷连续分布的带电体的电场场强 将其分割成点电荷系，任一电荷元 20dd4 rqEer积分： 20d4 rQqEerdEVPd qre步骤 (1)取电荷元 带电体 带电面 带电线 ddqlddqSddqV(2)求 ，取坐标系，投影；如是直角坐标系，即写出 dEd , d , dx y zE E E 。对称性分析 ,以简化计算
30、 ;定积分限的决定 . (3)积分 基本要点：先分解，后积分 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of t
31、he system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 例 电偶极子 ， 指一对等量、异号的点电荷，其间距远小于它们到考察点的距离的点电荷系统。 P ql 方向从负电荷指向正电荷 电偶极矩 q qp ql 求 (1）电偶极子轴线延长线上 A点的场强 ; (2）电偶极子中垂线上 B点的场强 ; (3)电偶极子在均匀外电场中受的力和力矩 . This paper mainly int roduces the design of an inteligent emperature cont rol system w
32、hich realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 204 ()2qEl r- 204 ()2qEl r 2201 ()4 22AqqEll
33、(r - ) (r ) 4 2 2024 (1 ) (1 )22q r lll r-rrlr3024 ApEr3024 ApEr考虑方向： q q xA 0r2l 2l 取如图坐标系 E(1)电偶极子轴线延长线上 A点的场强 E EThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al
34、 temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. （ 2）电偶极子中垂线上 B点的场强 如图选取坐标系 204 -qEE r 2 cosEE 2212220 22224 ( ) ( )22lqll rr 忽略， B点场强与 P反方向 4l 2304BpErE+E-E-q +q + - lrB y x 0 r r This paper
35、mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and
36、 DS18B20 t emperature sensor. (3)电偶极子在均匀外电场中受的力和力矩： 合力 EPM FFd力矩的大小为 sin sinM qE l pE 电偶极子处在外电场中时，其所受力矩总是使得电偶极子转向与外电场方向一致。 pE0F F F 垂直于 P、 E组成的平面且满足右螺旋法则。 MThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement a
37、nd cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 201dd4 xEr解： 取直角坐标 oxy如图 20dd d cos cos4xxEEr20dd d sin sin4yxEEr222s i ndrtan( ) cot2x d d 例 求真空中长为 L、
38、均匀带电，线电荷密度为 的直线的场强。场点与直线的垂直距离为 d、场点与直线两端连线和直线的夹角分别为 1和 2。 ddqx2dds i nxd均匀带电直线的场强 xyO d xEd yE 2 L d 12PdEd xxrThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temp
39、erature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. E20dd c o s4 xxEr 0d sin d4yE d 21 0cos d4xE d 0c o s d4 d 210sin sin4 d 2 yE E j jd0xE 即无限长均匀带电直线的场强，具有轴对称性。 120, l若 注意 211200sin d (cos cos )4 4yE
40、 dd This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr
41、 ocontroler and DS18B20 t emperature sensor. R 0 x例 带电量为 q、半径为 R的均匀带电圆环轴线上一点的场强 P x rdE20dd4 qEr由于对称性，全部元电荷的 被抵消 d E 带电圆环轴线上的场强 d d dqq l l2R解 取如图坐标系 线元 d ld E将 分解成 和 d E d E /dEEd的方向如图 dEThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function
42、 of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 所以，由对称性 当 dq 位置发生变化时，它所激发的电场 矢量构成了一个圆锥面。 Ed0 zy EE. qdRzxyEdxThis paper
43、 mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler an
44、d DS18B20 t emperature sensor. d cosxE E E 20co s d4 qr 20c o s4 qr304 qxr2 2 3 / 204 ()qxRx xx p R r qdEd32224 ()qxEixRE20dd4 qEr20co s d4 qr This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol b
45、y using single bus digit al temperature sensor DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 问题 6 6 求面电荷密度为 的，半径为 R的薄带电圆盘中心轴线 x处一点的电场强度。 圆盘可分割成许多带电细圆环 d d 2 dq s r r 320 2202 d4 R x r rErx 22320 220d2 2R rxxrx
46、 22012xRx均匀带电圆盘轴线上的场强 由例细圆环结果 2 2 3 / 204 ()xqERx2 2 3 / 20dd4 ()pxqErx R+ d rr解 建立坐标系 O x x pyzThis paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor
47、DS18B20 and single chip microcom puter. The core component s of the system ar e AT89C51 micr ocontroler and DS18B20 t emperature sensor. 无限大均匀带电平面的场强，匀强电场 2/1220 )(12 xRxE02E2204REx 204 qx可视为点电荷的电场 212222)1( xRxRx 2)(211xR（ 1） 当 Rx（ 2） 当 Rx讨论 This paper mainly int roduces the design of an inteligent emperature cont rol system which realizes the function of temper at ur e measurement and cont rol by using single bus digit al temperature sensor DS18B20 and single chip
