题目

Cultural rules determine every aspect of food consumption. Who eats together defines social units. For example, in some societies, the nuclear family is the unit that regularly eats together. The anthropologist Mary Douglas has pointed out that, for the English, the kind of meal and the kind of food that is served relate to the kinds of social links between people who are eating together. She distinguishes between regular meals, Sunday meals when relatives may come, and cocktail parties for relatives and friends. The food served symbolizes the occasion and reflects who is present. For 如图，一热敏电阻RT放在控温容器M内：A为毫安表，量程6 mA，内阻为数十欧姆；E为直流电源，电动势约为3V，内阻很小；R为电阻箱，最大阻值为999.9 Ω；S为开关。已知RT在95℃时的阻值为150 Ω，在20℃时的阻值约为550 Ω。现要求在降温过程中测量在95 ℃～20 ℃之间的多个温度下RT的阻值。 (1)在图中画出连线，完成实验原理电路图。(2)完成下列实验步骤中的填空： ①依照实验原理电路图连线；②调节控温容器M内的温度，使得RT的温度为95 ℃；③将电阻箱调到适当的初值，以保证仪器安全；④闭合开关，调节电阻箱，记录电流表示数I0，并记录____________；⑤将RT的温度降为T1(20 ℃＜T1＜95 ℃)，调节电阻箱，使得电流表的读数____________，记录_______________；⑥温度为T1时热敏电阻的电阻值RT1＝________________；⑦逐步降低T1的数值，直至20℃为止；在每一温度下重复步骤⑤、⑥。