第5课时测定电源的电动势和内阻【考纲解读】1.掌握用电流表和电压表测定电源的电动势和内阻的方法.2.掌握用图象处理实验数据的方法.3.掌握实物图连接的技巧．【知识要点】1．实验原理(1)实验依据：闭合电路欧姆定律．(2)E和r的求解：由U＝E－Ir得，解得E、r.(3)用作图法处理数据，如图1所示．INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\995.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\995.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\995.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\995.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\995.TIF"\*MERGEFORMATINETINCLUDEPICTURE"D:\\杨爱珍\\江苏\\word\\995.TIF"\*MERGEFORMATINET图1①图线与纵轴交点为E；②图线与横轴交点为I短＝；③图线的斜率表示r＝||.2．实验器材电池、电压表、电流表、滑动变阻器、开关、导线、坐标纸和刻度尺．3．基本操作(1)电流表用0.6A的量程，电压表用3V的量程，按实验原理图连接好电路．(2)把变阻器的滑片移到使阻值最大的一端．(3)闭合开关，调节变阻器，使电流表有明显示数并记录一组数据(I1、U1)．用同样的方法再测量几组I、U值，填入表格中．(4)断开开关，拆除电路，整理好器材．【典型例题】例1.(2014·福建·19(2))某研究性学习小组利用伏安法测定某一电池组的电动势和内阻，实验原理图如图甲所示，其中，虚线框内为用灵敏电流计INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈G.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈G.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈G.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\圈G.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\圈G.TIF"\*MERGEFORMATINETINCLUDEPICTURE"D:\\杨爱珍\\江苏\\word\\圈G.TIF"\*MERGEFORMATINET改装的1电流表INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈A.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈A.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈A.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\圈A.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\圈A.TIF"\*MERGEFORMATINETINCLUDEPICTURE"D:\\杨爱珍\\江苏\\word\\圈A.TIF"\*MERGEFORMATINET，INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈V.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈V.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈V.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\圈V.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\圈V.TIF"\*MERGEFORMATINETINCLUDEPICTURE"D:\\杨爱珍\\江苏\\word\\圈V.TIF"\*MERGEFORMATINET为标准电压表，E为待测电池组，S为开关，R为滑动变阻器，R0是标称值为4.0Ω的定值电阻．①已知灵敏电流计INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈G.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈G.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\圈G.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\圈G.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\圈G.TIF"\*MERGEFORMATINETINCLUDEPICTURE"D:\\杨爱珍\\江苏\\word\\圈G.TIF"\*MERGEFORMATINET的满偏电流为Ig＝100μA、内阻为rg＝2.0kΩ，若要改装后的电流表满偏电流为200mA，应并联一只________Ω(保留一位小数)的定值电阻R1；②根据图甲，用笔画线代替导线将图乙连接成完整的电路；INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\996.TIF"...
