Question

Mình cần gấp lắm

Answer 1

Bài 1.

\(R_1ntR_2\)

a)\(R_{tđ}=R_1+R_2=4+8=12\Omega\)

b)\(I_{mạch}=I_1=I_2=\dfrac{U}{R_{tđ}}=\dfrac{12}{12}=1A\)

\(U_1=I_1\cdot R_1=4\cdot1=4V\)

\(U_2=I_2\cdot R_2=8\cdot1=8V\)

Bài 2.

CTM: \(R_1ntR_2\)

\(\Rightarrow I_1=I_2=I_m=0,16A\)

\(U_1=I_1\cdot R_1=0,16\cdot50=8V\)

\(U_2=I_2\cdot R_2=0,16\cdot100=16V\)

\(U=U_1+U_2=8+16=24V\)

Answer 2

Bài 3.

\(R_1//R_2\Rightarrow R_{tđ}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{9\cdot6}{9+6}=3,6\Omega\)

\(U_1=U_2=U=7,2V\)

\(I_1=\dfrac{U_1}{R_1}=\dfrac{7,2}{9}=0,8A\)

\(I_2=\dfrac{U_2}{R_2}=\dfrac{7,2}{6}=1,2A\)

\(I=I_1+I_2=0,8+1,2=2A\)

Bài 4.

a)\(R_1//R_2\Rightarrow R_{tđ}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{10\cdot15}{10+15}=6\Omega\)

b)\(U_1=U_2=U=12V\)

\(I_1=\dfrac{U_1}{R_1}=\dfrac{12}{10}=1,2A\)

\(I_2=\dfrac{U_2}{R_2}=\dfrac{12}{15}=0,8A\)

c)Mắc thêm \(R_3=4\Omega\) thì: 

\(R_{tđ}=R_3+R_{12}=4+6=10\Omega\)

\(I_m=\dfrac{U_m}{R_m}=\dfrac{12}{10}=1,2A\)