Đáp án:
Rv/R=2/3
Giải thích các bước giải:
Theo đề bài
\(\left\{ \begin{align}
& {{R}_{2}}=2{{R}_{1}} \\
& {{U}_{1V}}=2V \\
& {{U}_{2V}}=3V \\
\end{align} \right.\)
\(\Leftrightarrow \left\{ \begin{align}
& {{I}_{1}}={{I}_{2}} \\
& {{U}_{1V}}={{I}_{1}}.{{R}_{1V}} \\
& {{U}_{2V}}={{I}_{2}}.{{R}_{2V}} \\
\end{align} \right.\)
=>
\(\dfrac{2}{3}=\dfrac{\frac{{{R}_{1}}.{{R}_{V}}}{{{R}_{1}}+{{R}_{V}}}}{\dfrac{{{R}_{2}}.{{R}_{V}}}{{{R}_{2}}+{{R}_{V}}}}\)
\(\Leftrightarrow \dfrac{{{R}_{1}}.{{R}_{V}}}{{{R}_{2}}.{{R}_{V}}}.\dfrac{{{R}_{2}}+{{R}_{V}}}{{{R}_{1}}+{{R}_{V}}}=\dfrac{2}{3}\Rightarrow \frac{1}{2}.\dfrac{2.{{R}_{1}}+{{R}_{V}}}{{{R}_{1}}+{{R}_{V}}}=\dfrac{2}{3}\Rightarrow 6{{R}_{1}}+3{{R}_{V}}=4{{R}_{1}}+4{{R}_{V}}\Rightarrow {{R}_{V}}=2{{R}_{1}}\)
Tỉ số:
\(\dfrac{{{R}_{V}}}{{{R}_{1}}+{{R}_{2}}}=\dfrac{2{{R}_{1}}}{3{{R}_{1}}}=\dfrac{2}{3}\)
