Bài 8:
\(MCD:R1//R2\)
\(\Rightarrow R12=\dfrac{R1\cdot R2}{R1+R2}=\dfrac{18\cdot12}{18+12}=7,2\Omega\)
\(U=U1=U2=36V\Rightarrow\left[{}\begin{matrix}I=\dfrac{U}{R}=\dfrac{36}{7,2}=5A\\I1=\dfrac{U1}{R1}=\dfrac{36}{18}=2A\\I2=\dfrac{U2}{R2}=\dfrac{36}{12}=3A\end{matrix}\right.\)
Bài 9: Xin mạch điện
Bài 9:
MCD: R1//R2
\(\Rightarrow U=U1=U2=I1\cdot R1=0,5\cdot15=7,5V\)
\(\Rightarrow I=\dfrac{U}{R}=\dfrac{7,5}{\dfrac{15\cdot10}{15+10}}=1,25A\)