Câu hỏi của Trần Duy Sang

\(R_1nt\left(R_2//R_3\right)\)\(R_{23}=\dfrac{R_2\cdot R_3}{R_2+R_3}=\dfrac{20\cdot30}{20+30}=12\Omega\)\(R_{tđ}=R_1+R_{23}=8+12=20\Omega\)\(I_A=I_m=\dfrac{U_m}{R_{tđ}}=\dfrac{45}{20}=2,25A\)Câu trả lời: \(R_1nt\left(R_2//R_3\right)\)\(R_{23}=\dfrac{R_2\cdot R_3}{R_2+R_3}=\dfrac{20\cdot30}{20+30}=12\Omega\)\(R_{tđ}=R_1+R_{23}=8+12=20\Omega\)\(I_A=I_m=\dfrac{U_m}{R_{tđ}}=\dfrac{45}{20}=2,25A\)