Bài 5:
\(MCD:R_1nt\left(R_2//R_3\right)\)
\(\rightarrow R=R_1+\dfrac{R_2\cdot R_3}{R_2+R_3}=12+\dfrac{15\cdot25}{15+25}=21,375\Omega\)
Ta có: \(U_2=U_3=U_{23}=I_2R_2=0,2\cdot15=3V\)
\(\rightarrow I_{23}=I_2+I_3=0,2+\dfrac{3}{25}=0,32A\)
\(\rightarrow\left\{{}\begin{matrix}U_1=I_1R_1=0,32\cdot12=3,84V\\U=IR=0,32\cdot21,375=6,84V\end{matrix}\right.\)
Bài 6:
\(MCD:R_1ntR_2\)
\(\rightarrow R=R_1+R_2=12+10=22\Omega\)
Ta có: \(I=I_1=I_2=\dfrac{U_1}{R_1}=\dfrac{12}{12}=1A\)
\(\rightarrow U=IR=1\cdot22=22V\)