Question

Answer 1

\(MCD:R_1ntR_2\)

\(\Rightarrow R_{td}=R_1+R_2=4+6=10\Omega\)

\(\Rightarrow I=\dfrac{U}{R_{td}}=\dfrac{18}{10}=1,8A\)

\(MCD:R_1nt\left(R_2//R_3\right)\)

\(\Rightarrow R_{td}'=R_1+\dfrac{R_2\cdot R_3}{R_2+R_3}=4+\dfrac{6\cdot12}{6+12}=8\Omega\)

\(\Rightarrow I'=\dfrac{U}{R_{td}'}=\dfrac{18}{8}=2,25A\)

Answer 2

a)\(R_{tđ}=R_1+R_2=4+6=10\Omega\)

\(I_{AB}=\dfrac{U}{R}=\dfrac{18}{10}=1,8A\)

b)\(R_1nt\left(R_2//R_3\right)\)

\(R_{tđ}=R_1+\dfrac{R_2\cdot R_3}{R_2+R_3}=4+\dfrac{6\cdot12}{6+12}=8\Omega\)

\(I=\dfrac{U}{R}=\dfrac{18}{8}=2,25A\)