\(240:4=60\left(cm\right)\)

1B

2A

3D

4C

Uhm, thiếu đoạn văn nhé!

Bài 1:

a. \(R=R1+\left(\dfrac{R2.R3}{R2+R3}\right)=30+\left(\dfrac{15\cdot10}{15+10}\right)=36\Omega\)

b. \(I=I1=I23=\dfrac{U}{R}=\dfrac{24}{36}=\dfrac{2}{3}A\left(R1ntR23\right)\)

\(U23=U2=U3=I23\cdot R23=\dfrac{2}{3}\cdot\left(\dfrac{15.10}{15+10}\right)=4V\left(R2\backslash\backslash R3\right)\)

\(\rightarrow\left\{{}\begin{matrix}I2=U2:R2=4:15=\dfrac{4}{15}A\\I3=U3:R3=4:10=0,4A\end{matrix}\right.\)

Bài 2:

a. \(R=\dfrac{R1.\left(R2+R3\right)}{R1+R2+R3}=\dfrac{6\cdot\left(2+4\right)}{6+2+4}=3\Omega\)

b. \(U=IR=2.3=6V\)

Kết quả đúng rồi bạn nhé!

2. Tìm R₃:

\(U_{23}=U_2=U_3=I_2\cdot R_2=2.1=2V\left(R_2\backslash\backslash R_3\right)\)

\(U_1=U-U_{23}=18-2=16V\)

\(\rightarrow I=I_1=I_{23}=\dfrac{U_1}{R_1}=\dfrac{16}{3}=\dfrac{16}{3}A\left(R_1ntR_{23}\right)\)

\(\rightarrow I_3=I_{23}-I_2=\dfrac{16}{3}-2=\dfrac{10}{3}A\)

\(\Rightarrow R_3=\dfrac{U_3}{I_3}=\dfrac{2}{\dfrac{10}{3}}=0,6\Omega\)

1. Tìm R₁:

\(U_{23}=U_2=U_3=I_2\cdot R_2=2\cdot6=12V\left(R_2\backslash\backslash R_3\right)\)

\(I=I_1=I_{23}=\dfrac{U_{23}}{R_{23}}=\dfrac{12}{\dfrac{6.3}{6+3}}=6A\left(R_1ntR_{23}\right)\)

\(\Rightarrow R_1=\dfrac{U_1}{I_1}=\dfrac{\left(18-12\right)}{6}=1\Omega\)

\(H_2O\)

Số 2 là hai phân tử Hidro nhé!