Đáp án:
\(\begin{array}{l}
1.\\
a.\\
R = 10\Omega \\
P = 5,625W\\
b.U' = \dfrac{{60}}{{13}}V\\
2.\\
a.\\
R = \dfrac{{24}}{7}\Omega \\
P = \dfrac{6}{7}{\rm{W}}\\
b.U' = \dfrac{{59}}{{14}}V
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
1.\\
a.\\
R = {R_1} + {R_2} = 4 + 6 = 10\Omega \\
P = R{I^2} = 10.0,{75^2} = 5,625W\\
b.\\
R' = \dfrac{{R{R_3}}}{{R + {R_3}}} = \dfrac{{10.16}}{{10 + 16}} = \dfrac{{80}}{{13}}\Omega \\
U' = {\rm{IR}}' = 0,75.\dfrac{{80}}{{13}} = \dfrac{{60}}{{13}}V\\
2.\\
a.\\
R = \dfrac{{{R_1}{R_2}}}{{{R_1} + {R_2}}} = \dfrac{{6.8}}{{6 + 8}} = \dfrac{{24}}{7}\Omega \\
P = R{I^2} = \dfrac{{24}}{7}.0,{5^2} = \dfrac{6}{7}{\rm{W}}\\
b.\\
R' = R + {R_3} = \dfrac{{24}}{7} + 5 = \dfrac{{59}}{7}\Omega \\
U' = {\rm{IR}}' = 0,5.\dfrac{{59}}{7} = \dfrac{{59}}{{14}}V
\end{array}\)
