题目

It was the boy, rather than his teachers, that for what the boy had done. A . were to blame B . were to be blamed C . was to blame D . was to be blamed 答案：C6．汽车尾气是造成空气污染的原因之一，某物理实验小组设计了如图所示的有害尾气排放检测原理图．已知电源电压12V不变，R0为定值电阻，R为气敏电阻，气敏电阻的阻值随有害尾气浓度变化的部分数据如下表所示．有害尾气浓度%VOL…57.51012.515…R/Ω…5.2432.52…（1）当电压表的读数为8V时，电流表的读数为1A，求电阻R0的阻值．（2）当这种有害尾气浓度增大到15%VOL时，求电压表的示数．（3）当电路消耗的总功率为18W时，有害尾气的浓度是多少？