Đáp án:
\(\dfrac{{{Q_1}'}}{{{Q_1}}} = \dfrac{3}{2}\)
Giải thích các bước giải:
* Ban đầu:
\(\begin{array}{l}
\dfrac{{{U_1}}}{{{U_2}}} = \dfrac{{{C_2}}}{{{C_1}}} = \dfrac{1}{2} \Rightarrow {U_2} = 2{U_1}\\
\Rightarrow {Q_1} = {U_1}{C_1} = \dfrac{U}{3}{C_1}
\end{array}\)
* Lúc sau:
\(\begin{array}{l}
\dfrac{{{U_1}'}}{{{U_2}'}} = \dfrac{{{C_2}'}}{{{C_1}}} = 1 \Rightarrow {U_2}' = {U_1}'\\
\Rightarrow {Q_1}' = {U_1}'{C_1} = \dfrac{U}{2}{C_1}
\end{array}\)
Suy ra: \(\dfrac{{{Q_1}'}}{{{Q_1}}} = \dfrac{3}{2}\)