9.
小明同学通过实验探究某一金属电阻的阻值 \(R\)随温度 \(t\)的变化关系\(.\)已知该金属电阻在常温下的阻值约\(10Ω\), \(R\)随 \(t\)的升高而增大\(.\)实验电路如图所示,控温箱用以调节金属电阻的温度.
实验时闭合\(S_{1}\),先将开关\(S_{2}\)与\(1\)端闭合,调节金属电阻的温度,分别记下温度\(t\)\({\,\!}_{1}\),\(t\)\({\,\!}_{2}…\)和电流表的相应示数\(I\)\({\,\!}_{1}\),\(I\)\({\,\!}_{2}\),\(….\)然后将开关\(S_{2}\)与\(2\)端闭合,调节电阻箱使电流表的示数再次为\(I\)\({\,\!}_{1}\),\(I\)\({\,\!}_{2}\),\(…\),分别记下电阻箱相应的示数\(R\)\({\,\!}_{1}\),\(R\)\({\,\!}_{2}\),\(…\).
\((1)\)有以下两种电流表,实验电路中应选用________.
A.量程\(0~100 mA\),内阻约\(2 ΩB.\)量程\(0~0.6 A\),内阻可忽略
\((2)\)实验过程中,要将电阻箱的阻值由\(9.9Ω\)调节至\(10.0Ω\),需旋转图中电阻箱的旋钮“\(a\)”“\(b\)”“\(c\)”,正确的操作顺序是________.
\(①\)将旋钮\(a\)由“\(0\)”旋转至“\(1\)”
\(②\)将旋钮\(b\)由“\(9\)”旋转至“\(0\)”
\(③\)将旋钮\(c\)由“\(9\)”旋转至“\(0\)”
\((3)\)实验记录的\(t\)和\(R\)的数据见下表:
温度\(t\)\((℃)\) | \(20.0\) | \(40.0\) | \(60.0\) | \(80.0\) | \(100.0\) |
阻值\(R\)\((Ω)\) | \(9.6\) | \(10.4\) | \(11.1\) | \(12.1\) | \(12.8\) |
请根据表中数据,在方格纸上作出\(R\)\(-\)\(t\)图线.
由图线求得\(R\)随\(t\)的变化关系为\(R\)\(=\)________\(Ω\).