Đáp án:
\(\begin{array}{l}
a.\\
{U_2}' = 8333,333V\\
b.\\
{U_2}' = 8416,667V
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a.\\
\frac{{{U_1}}}{{{U_2}}} = \frac{{{N_1}}}{{{N_2}}}\\
\frac{{250}}{{{U_2}}} = \frac{{600}}{{20000}}\\
{U_2} = 8333,333V
\end{array}\)
b.
\(\begin{array}{l}
\frac{{{U_1}}}{{{U_2}'}} = \frac{{{N_1}}}{{{N_2}'}}\\
\frac{{250}}{{{U_2}'}} = \frac{{600}}{{20000 + 200}}\\
{U_2}' = 8416,667V
\end{array}\)