Lời giải:

a) \[{R_{12}} = {R_1} + {R_2} = 1 + 2 = 3\,\Omega \]

\[{R_{td}} = \frac{{{R_{12}}.{R_3}}}{{{R_{12}} + {R_3}}} = \frac = 1,5\,\Omega \]

b) \[U = {U_{12}} = {U_3} = 6\,V\]

\[{I_{12}} = {I_1} = {I_2} = \frac{{{U_{12}}}}{{{R_{12}}}} = \frac{6}{3} = 2\,A\]

\[{I_3} = \frac{}{} = \frac{6}{3} = 2\,A\]

c) \[P = \frac{{{U^2}}}{{{R_{td}}}} = \frac{{{6^2}}}{{1,5}} = 24\,W\]