Question

Answer 1

R3 nt (R1//R2)

a,\(\Rightarrow U1=U2=I2R2=1,5.6=9V\)

\(\Rightarrow I3=I12=\dfrac{Uab-U2}{R3}=3A\Rightarrow I1=I3-I2=1,5A\Rightarrow R1=\dfrac{U1}{I1}=6\Omega\)

b, \(\Rightarrow Rtd=6+\dfrac{4R2}{4+R2}\left(\Omega\right)\)

\(\Rightarrow I3=I1+I2\Rightarrow\dfrac{24}{6+\dfrac{4R2}{4+R2}}=1,5+\dfrac{1,5.R2}{4}\Rightarrow R2=4\Omega\)

c,\(\Rightarrow U1=U2=I2R2=18V\Rightarrow U3=24-18=6V\)

\(\Rightarrow R3=\dfrac{6}{Im}=\dfrac{6}{I12}=\dfrac{6}{\dfrac{18}{R12}}=\dfrac{6}{\dfrac{18}{\dfrac{6.12}{6+12}}}=\dfrac{6}{4,5}=\dfrac{4}{3}\Omega\)