Đáp án:
$U=150V$
Giải thích các bước giải:
$u=75\sqrt{6}V;{{u}_{RL}}=25\sqrt{6}V;{{U}_{R}}=75V$
khi:
${{U}_{Cmax}}\Rightarrow \overrightarrow{U}\bot \overrightarrow{{{U}_{RL}}}$
ta có:
$\left\{ \begin{align}
& \dfrac{{{u}^{2}}}{{{U}^{2}}}+\dfrac{u_{RL}^{2}}{U_{RL}^{2}}=2 \\
& \frac{1}{U_{R}^{2}}=\dfrac{1}{{{U}^{2}}}+\dfrac{1}{U_{RL}^{2}} \\
\end{align} \right.$
thay số:
$\Leftrightarrow \left\{ \begin{align}
& \dfrac{{{(75\sqrt{6})}^{2}}}{{{U}^{2}}}+\dfrac{{{(25\sqrt{6})}^{2}}}{U_{RL}^{2}}=2 \\
& \dfrac{1}{75}=\dfrac{1}{{{U}^{2}}}+\dfrac{1}{U_{RL}^{2}} \\
\end{align} \right.$
$\Rightarrow \left\{ \begin{align}
& \frac{1}{{{U}^{2}}}=\dfrac{1}{22500} \\
& \frac{1}{U_{RL}^{2}}=\dfrac{1}{7500} \\
\end{align} \right.$
$\Rightarrow \left\{ \begin{align}
& U=150V \\
& {{U}_{RL}}=50\sqrt{3}V \\
\end{align} \right.$