题目内容
硅光电池是一种太阳能电池,具有低碳环保的优点.如图所示,图线a是该电池在某光照强度下路端电压U和电流I的关系图象(电池内阻不是常数),图线b是某电阻R的U-I图象.当它们组成闭合回路时,硅光电池的内阻可表示为( )![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_ST/images0.png)
A.
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_ST/0.png)
B.
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_ST/1.png)
C.
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_ST/2.png)
D.
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_ST/3.png)
【答案】分析:由欧姆定律得U=E-Ir,
的大小等于r,当I=0时,E=U,由图可知电池的电动势为U2.当电流为I1时,根据欧姆定律求出内阻.
解答:解:A、由欧姆定律得U=E-Ir,
的大小等于r,即a图线切线的斜率大小等于内阻.由图可知r=
.故A正确.
B、由欧姆定律得U=E-Ir,当I=0时,E=U,由a与纵轴的交点读出电动势为E=U2.根据两图线交点处的状态可知,电阻的电压为U1,则内阻r=
=
.故B正确.
C、电阻为线性元件,
=R.故C错误.
D、由欧姆定律得U=E-Ir,
的大小等于r,而由图可知![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/7.png)
,则
.故D错误.
故选AB
点评:本题考查对图象的理解能力.对于线性元件R=
,对于非线性元件,R=
.对于电源的内阻往往根据电源的外特性曲线研究斜率得到.
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/0.png)
解答:解:A、由欧姆定律得U=E-Ir,
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/1.png)
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/2.png)
B、由欧姆定律得U=E-Ir,当I=0时,E=U,由a与纵轴的交点读出电动势为E=U2.根据两图线交点处的状态可知,电阻的电压为U1,则内阻r=
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/3.png)
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/4.png)
C、电阻为线性元件,
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/5.png)
D、由欧姆定律得U=E-Ir,
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/6.png)
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/7.png)
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/8.png)
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/9.png)
故选AB
点评:本题考查对图象的理解能力.对于线性元件R=
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/10.png)
![](http://thumb.1010pic.com/pic6/res/gzwl/web/STSource/20131029191400599810810/SYS201310291914005998108001_DA/11.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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