a)\(R_1ntR_2\Rightarrow R_{tđ}=R_1+R_2=6+10=16\Omega\)
\(I_1=I_2=I=\dfrac{U}{R_{tđ}}=\dfrac{42}{16}=2,625A\)
\(U_1=I_1\cdot R_1=2,625\cdot6=15,75V\)
\(U_2=U-U_1=42-15,75=26,25V\)
\(P=U\cdot I=42\cdot2,625=110,25W\)
b)\(R_Đ=\dfrac{U_Đ^2}{P_Đ}=\dfrac{12^2}{12}=12\Omega;I_{Đđm}=\dfrac{P_Đ}{U_Đ}=\dfrac{12}{12}=1A\)
\(\left(R_1//Đ\right)ntR_2\)
\(R_{1Đ}=\dfrac{R_1\cdot R_Đ}{R_1+R_Đ}=\dfrac{6\cdot12}{6+12}=4\Omega\)
\(R_{tđ}=R_2+R_{1Đ}=10+4=14\Omega\)
\(I_2=I_{1Đ}=I_{mạch}=\dfrac{U}{R_{tđ}}=\dfrac{42}{14}=3A\)
\(U_Đ=U_{1Đ}=I_{1Đ}\cdot R_{1Đ}=3\cdot4=12V\)
\(I_Đ=\dfrac{U_Đ}{R_Đ}=\dfrac{12}{12}=1A=I_{Đđm}\)
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