Question

Giúp mình với

Answer 1

\(R_{tđ}=R_1+R_2=8+12=20\Omega\)

\(I_m=\dfrac{U}{R}=\dfrac{24}{20}=1,2A\)

\(R_3//\left(R_1ntR_2\right)\)

\(R'_{tđ}=\dfrac{U}{I'}=\dfrac{24}{2}=12\Omega\)

Mà \(R_{tđ}=\dfrac{R_3\cdot R_{12}}{R_3+R_{12}}=\dfrac{R_3\cdot20}{R_3+20}=12\)

\(\Rightarrow R_3=30\Omega\)