a. R1 // R2

-> $R12=\dfrac{R1.R2}{R1+R2}=$ $\dfrac{2.3}{2+3}=1,2(ôm)$ 

R12 // R3

-> $Rtđ=\dfrac{R12.R3}{R12+R3}=\dfrac{1,2.6}{1,2+6}=1(ôm)$ 

b. R1 // R2 // R3

-> U1 = U2 = U3 = U = 6 V

$I1=\dfrac{U1}{R1}=\dfrac{6}{2}=3(A)$

$I2=\dfrac{U2}{R2}=\dfrac{6}{3}=2(A)$

$I3=\dfrac{U3}{R3}=\dfrac{6}{6}=1(A)$

$Itm=\dfrac{U}{Rtd}=\dfrac{6}{1}=6(A)$

Chúc bạn học tốt !!!!

Bạn tham khảo!

$\text{Tóm tắt:}$

$\rightarrow$ $\text{R1=2$\Omega$}$

$\rightarrow$ $\text{R2=3$\Omega$}$

$\rightarrow$ $\text{R3=6$\Omega$}$

$\text{Giải:}$

$\text{a) Vì là mạch song song:}$

$\rightarrow$ $\text{$\frac{1}{Rtđ}$=$\frac{1}{R1}$+$\frac{1}{R2}$+$\frac{1}{R3}$}$

$\text{Thế số:}$

$\rightarrow$ $\text{$\frac{1}{Rtđ}$=$\frac{1}{2}$+$\frac{1}{3}$+$\frac{1}{6}$}$=1}$

$\rightarrow$ $\text{Rtđ=1$\Omega$}$

$\text{b) Vì là mạch song song nên UAB=U1=U2=U3=6V}$

$\text{IAB=$\frac{UAB}{Rtđ}$ =$\frac{6}{1}$=6A}$
$\text{I1=$\frac{U1}{R1}$=$\frac{6}{2}$=3A}$

$\text{I2=$\frac{U2}{R2}$=$\frac{6}{3}$=2A}$

$\text{I3=$\frac{U3}{R3}$=$\frac{6}{6}$=1A}$

#TRANPHAMGIABAO