问题 实验题

现有器材:热敏电阻RT(80Ω∽200Ω)、温度计、一杯水、电源(6V,内阻可忽略)、电流表(量程60mA,内阻约10Ω) 、电压表(量程10V,内阻约20kΩ) 、电键、酒精灯、导线若干。某同学根据现有器材设计电路探究热敏电阻RT随温度t变化的关系,并连接了部分实物,如图丙所示。

①在图丙的实物图上完成电路连线。

②用酒精灯对水加热,该同学测得不同温度下的电流和电压值。由下表数据,可计算出t =520C时RT =____Ω;

请在图丁中描出相应的点,并作出RT—t图线。

温度t(0C)304252637380
电压U(V)5.445.355.275.205.004.97
电流I(mA)27.230.634.240.046.352.3
RT阻值Ω200175 13010895
 

③由图线可知,热敏电阻RT阻值随温度t均匀减小,变化率为_______(保留三位有效数字)。

答案

①电路连线见解析。② RT=154Ω;RT—t图线见解析;③2.13 ( 2.08~2.18之间,同样给分)

题目分析:①因为,而,故采用电压表内接电路;电路连线如图:

② t =520C时;RT—t图线见下图:

③热敏电阻RT阻值随温度t变化率为:T随温度t变化的关系.

阅读理解

阅读理解

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