Question

Answer 1

\(MCD:R1//R2\)

\(=>R=\dfrac{R1\cdot R2}{R1+R2}=\dfrac{4\cdot12}{4+12}=3\Omega\)

\(U=U1=U2=12V=>\left\{{}\begin{matrix}I=U:R=12:3=4A\\I1=U1:R1=12:4=3A\\I2=U2:R2=12:12=1A\end{matrix}\right.\)

\(=>Q_{toa}=A=UIt=12\cdot4\cdot10\cdot60=28800\left(J\right)\)

Answer 2

\(R_{12}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{4\cdot12}{4+12}=3\Omega\)

\(I=\dfrac{U}{R}=\dfrac{12}{3}=4A\)

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

\(I_1=\dfrac{U_1}{R_1}=\dfrac{12}{4}=3A\)

\(I_2=I-I_1=4-3=1A\)

\(A_1=U_1\cdot I_1\cdot t=12\cdot3\cdot10\cdot60=21600J\)