Question

Giúp mình 3 câu này gấp ạ

Answer 1

Câu 3.

a)CTM: \(\left(R_1//R_2\right)ntR_3\)

\(R_{12}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{10\cdot15}{10+15}=6\Omega\)

\(R_{AB}=R_{12}+R_3=6+9=15\Omega\)

b)\(U_{AB}=15V\)

\(I_3=I_{12}=\dfrac{U}{R}=\dfrac{15}{15}=1A\)

\(U_1=U_2=U_{12}=I_{12}\cdot R_{12}=1\cdot6=6V\)

\(I_1=\dfrac{U_1}{R_1}=\dfrac{6}{10}=0,6A;I_2=\dfrac{U_2}{R_2}=\dfrac{6}{15}=0,4A\)

Answer 2

Câu 1.

\(I_A=I=0,5A\)

a)\(R_{AB}=\dfrac{U}{I}=\dfrac{6}{0,5}=12\Omega\)

b)\(R_1ntR_2\Rightarrow R_2=R_{AB}-R_1=12-5=7\Omega\)

Câu 2.

a)\(R_1//R_2\Rightarrow R_{tđ}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{30\cdot15}{30+15}=10\Omega\)

Hiệu điện thế giữa hai đầu đoạn mạch: \(U=R\cdot I=10\cdot0,8=8V\)

b)\(U_1=U_2=U=8V\)

\(I_1=\dfrac{U_1}{R_1}=\dfrac{8}{30}=\dfrac{4}{15}A;I_2=\dfrac{U_2}{R_2}=\dfrac{8}{15}A\)