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1、内容与要求1.通过实验，认识交变电流.能用公式和图象描述正弦交变电流.2.通过实验，探究并了解变压器原、副线圈电压与匝数的关系.了解从变电站到用户的输电过程，知道远距离输电时用高电压的道理.3.了解发电机和电动机工作过程中的能量转化.认识电磁学在人类生活和社会发展中的作用.4.知道非电学量转化成电学量的技术意义.5.通过实验，了解常见传感器的工作原理.会利用传感器设计并制作简单的自动控制装置.6.列举传感器在生产生活中的应用.第 1 讲交变电流的产生和描述一、正弦式交变电流1.产生线圈绕垂直于磁场方向的轴匀速转动.2.两个特殊位置的特点(1)线圈平面与中性面重合时，SB，最大，t0，e0，i0
2、，电流方向将发生改变.(2)线圈平面与中性面垂直时，SB，0，t最大，e 最大，i 最大，电流方向不改变.3.电流方向的改变一个周期内线圈中电流的方向改变两次.4.交变电动势的最大值EmnBS，与转轴位置无关，与线圈形状无关.5.交变电动势随时间的变化规律(中性面开始计时)enBS sin t.自测 1(多选)关于中性面，下列说法正确的是()A.线圈在转动中经中性面位置时，穿过线圈的磁通量最大，磁通量的变化率为零B.线圈在转动中经中性面位置时，穿过线圈的磁通量为零，磁通量的变化率最大|精.|品.|可.|编.|辑.|学.|习.|资.|料.*|*|*|*|欢.|迎.|下.|载.第 1 页，共 18
3、 页C.线圈每经过一次中性面，感应电流的方向就改变一次D.线圈每转动一周经过中性面一次，所以线圈每转动一周，感应电流的方向就改变一次答案AC 二、描述交变电流的物理量1.周期和频率(1)周期 T：交变电流完成1 次周期性变化所需要的时间，单位是秒(s).表达式为T21n(n 为转速).(2)频率 f：交变电流在1 s 内完成周期性变化的次数，单位是赫兹(Hz).(3)周期和频率的关系：T1f或 f1T.2.交变电流的瞬时值、最大值、有效值和平均值(1)瞬时值：交变电流某一时刻的值.(2)最大值：交变电流或电压所能达到的最大的值.(3)有效值：让恒定电流和交变电流分别通过阻值相等的电阻，如果在交
4、流的一个周期内它们产生的热量相等，就可以把恒定电流的数值规定为这个交变电流的有效值.(4)正弦式交变电流的有效值与最大值之间的关系IIm2，UUm2，EEm2.(5)交变电流的平均值E n t，I n Rr t.自测 2(2018 安徽省安庆市二模)小型手摇发电机线圈共有N 匝，每匝可简化为矩形线圈abcd，磁极间的磁场视为匀强磁场，磁感应强度大小为B，方向垂直于线圈中心轴OO，线圈绕OO匀速转动，如图1 所示.矩形线圈ab 边和 cd 边产生的感应电动势的最大值都为E0，该发电机外接负载电阻，则()图 1 A.当线圈处于中性面位置时磁通量的变化率最大B.线圈从中性面位置转过180 过程中，线
5、圈中磁通量的变化量为零C.线圈转动过程中电动势的有效值为22NE0D.线圈转动过程中电动势的最大值为2NE0答案D 解析当线圈处于中性面位置时磁通量最大，磁通量的变化率为零，选项A 错误；线圈从中性面|精.|品.|可.|编.|辑.|学.|习.|资.|料.*|*|*|*|欢.|迎.|下.|载.第 2 页，共 18 页文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B
6、10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档
7、编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2
8、J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X
9、6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX
10、7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7
11、G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:C
12、K10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1位置转过180 过程中，线圈中磁通量的变化量为2BS，选项 B 错误；矩形线圈 ab 边和 cd 边产生的感应电动势的最大值都为E0，所以矩形线圈产生的感应电动势的最大值是2NE0，电动势的有效值U2E0N22NE0，选项 C 错误，D 正确.命题点一交变电流
13、的产生及变化规律1.交变电流的变化规律(线圈在中性面位置开始计时)规律物理量函数表达式图象磁通量mcos tBScos t电动势eEmsin tnBSsin t电压uUmsin tREmRrsin t电流iImsin tEmRrsin t2.交变电流瞬时值表达式的书写(1)确定正弦交变电流的峰值，根据已知图象读出或由公式EmnBS 求出相应峰值.(2)明确线圈的初始位置，找出对应的函数关系式.如：线圈在中性面位置开始计时，则it 图象为正弦函数图象，函数表达式为i Imsin t.线圈在垂直于中性面的位置开始计时，则it 图象为余弦函数图象，函数表达式为iImcos t.例 1(多选)(201
14、6 全国卷 21)如图 2，M 为半圆形导线框，圆心为OM；N 是圆心角为直角的扇形导线框，圆心为ON；两导线框在同一竖直面(纸面)内；两圆弧半径相等；过直线OMON的水平面上方有一匀强磁场，磁场方向垂直于纸面.现使线框M、N 在 t0 时从图示位置开始，分别绕垂直于纸面且过OM和 ON的轴，以相同的周期T 逆时针匀速转动，则()|精.|品.|可.|编.|辑.|学.|习.|资.|料.*|*|*|*|欢.|迎.|下.|载.第 3 页，共 18 页文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6
15、ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y
16、3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G1
17、0T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK1
18、0B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1
19、文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10
20、Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G
21、9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1图 2 A.两导线框中均会产生正弦交流电B.两导线框中感应电流的周期都等于TC.在 tT8时，两导线框中产生的感应电动势相等D.
22、两导线框的电阻相等时，两导线框中感应电流的有效值也相等答案BC 解析两导线框进入磁场过程中，匀速转动切割磁感线产生感应电动势的大小不变，选项A 错误；导线框的转动周期为T，则感应电流的周期也为T，选项 B 正确；在 tT8时，切割磁感线的有效长度相同，两导线框中产生的感应电动势相等，选项C 正确；M 导线框中一直有感应电流，N 导线框中只有一半时间内有感应电流，所以两导线框的电阻相等时，感应电流的有效值不相等，选项D错误.变式 1(多选)(2019 河北省衡水金卷模拟一)如图 3 所示，线圈 ABCD 匝数 n10，面积 S0.4 m2，边界 MN(与线圈的 AB 边重合)右侧存在磁感应强度B
23、2T 的匀强磁场，若线圈从图示位置开始绕AB 边以 10 rad/s 的角速度匀速转动.则以下说法正确的是()图 3 A.线圈产生的是正弦交流电B.线圈在转动过程中产生的最大感应电动势为80 V C.线圈转动160s 时瞬时感应电动势为40 3 V D.线圈产生的感应电动势的有效值为40 V 答案BD 解析线圈在有界匀强磁场中将产生正弦半波脉动电流，故 A 错误；电动势最大值EmnBS 80 V，故 B 正确；线圈转动160s、转过角度6，瞬时感应电动势为eEmsin 640 V，故 C 错误；在一个周期时间内，只有半个周期产生感应电动势，根据有效值的定义有(Em2R)2RT2(ER)2RT，
24、可得电|精.|品.|可.|编.|辑.|学.|习.|资.|料.*|*|*|*|欢.|迎.|下.|载.第 4 页，共 18 页文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1
25、 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B1
26、0K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编
27、码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J
28、8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6
29、 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7
30、Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G
31、10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1动势有效值EEm240 V，故 D 正确.例 2(2018 安徽省宣城市第二次调研)图 4 甲为小型旋转电枢式交流发电机的原理图，其矩形线圈在磁感应强度为B的匀强磁场中，绕垂直于磁场方向的固定轴OO(OO沿水平方向)匀速转动，线圈的两端经集流环和电刷与电阻R10 连接，与电阻R 并联的交流电压表为理想电压表，示数是 10 V.图乙是矩形线圈中磁通量随时间t 变化的图象.线圈内阻不计，则()图 4 A.此交流发电机的电动势平均值为10 2 V B.t0
32、.02 s 时 R 两端的电压瞬时值为零C.R 两端的电压u 随时间 t 变化的规律是u102cos(100t)V D.当 ab 边速度方向向上时，它所受安培力的方向也向上答案C 解析矩形线圈绕垂直于磁场的转轴匀速转动，产生正弦交流电，外电阻R 10 ，电压表示数为10 V，说明Em210 V，即电动势最大值为Em102 V，所以平均值一定比Em102 V 小，选项A 错.根据题图乙知t0 时磁通量等于0，可判断t0 时电动势最大，所以电动势随时间变化的规律为 uEmcos t 102cos(100 t)V，选项 C 对.将 t0.02 s 代入电动势瞬时值表达式，得 U102 V，选项 B
33、错.根据楞次定律，感应电流总是阻碍线圈的转动，所以当ab 边速度方向向上时，它所受安培力的方向向下，选项D 错.变式 2(多选)(2013 山东卷 17)图 5 甲是小型交流发电机的示意图，两磁极 N、S 间的磁场可视为水平方向的匀强磁场，为交流电流表.线圈绕垂直于磁场的水平轴OO沿逆时针方向匀速转动，从图示位置开始计时，产生的交变电流随时间变化的图象如图乙所示.以下判断正确的是()|精.|品.|可.|编.|辑.|学.|习.|资.|料.*|*|*|*|欢.|迎.|下.|载.第 5 页，共 18 页文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:
34、CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I
35、7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 Z
36、N10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3
37、X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10
38、T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10
39、B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文
40、档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1图 5 A.电流表的示数为10 A B.线圈转动的角速度为50 rad/s
41、C.0.01 s 时线圈平面与磁场方向平行D.0.02 s 时电阻 R 中电流的方向自右向左答案AC 解析电流表测量的是电路中电流的有效值I 10 A，选项 A 正确.由图象可知，T 0.02 s，所以 2T100 rad/s，选项 B 错误.t0.01 s 时，电流最大，线圈平面与磁场方向平行，选项C 正确.t0.02 s 时，线圈所处的状态就是图示状况，此时R 中电流的方向自左向右，选项D 错误.命题点二交流电有效值的求解1.交变电流有效值的规定交变电流、恒定电流I直分别通过同一电阻R，在交流的一个周期内产生的焦耳热分别为Q交、Q直，若 Q交Q直，则交变电流的有效值II直(直流有效值也可以
42、这样算).2.对有效值的理解(1)交流电流表、交流电压表的示数是指有效值；(2)用电器铭牌上标的值(如额定电压、额定功率等)指的均是有效值；(3)计算热量、电功率及保险丝的熔断电流指的是有效值；(4)没有特别加以说明的，是指有效值；(5)“交流的最大值是有效值的2倍”仅适用于正(余)弦式交变电流.3.计算交变电流有效值的方法(1)计算有效值时要根据电流的热效应，抓住“三同”：“相同时间”内“相同电阻”上产生“相同热量”列式求解.(2)分段计算电热求和得出一个周期内产生的总热量.(3)利用两个公式QI2Rt 和 QU2Rt 可分别求得电流有效值和电压有效值.(4)若图象部分是正弦(或余弦)式交变
43、电流，其中的14周期(必须是从零至最大值或从最大值至零)和12周期部分可直接应用正弦式交变电流有效值与最大值间的关系IIm2、UUm2求解.例 3(2018 全国卷 16)一电阻接到方波交流电源上，在一个周期内产生的热量为Q方；若该电阻接到正弦交流电源上，在一个周期内产生的热量为Q正.该电阻上电压的峰值均为u0，周期均为T，如图 6 所示.则 Q方Q正等于()|精.|品.|可.|编.|辑.|学.|习.|资.|料.*|*|*|*|欢.|迎.|下.|载.第 6 页，共 18 页文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10
44、T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10
45、B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文
46、档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y
47、2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9
48、X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 H
49、X7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K
50、7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1文档编码:CK10B10K7G10T1 HX7Y3X8G9X6 ZN10Y2J8I7I1图 6 A.12 B.21 C.12 D.21 答案D 解析由有效值概念知，一个周期内产生热量Q方