According to the diagram - Total current I = 1 amp is entering the parallel combination of R1 and R. Let I1 current flows through R1 and I2 current flows through R2
Then
$\text{I}_1=\frac{\text{IR}_2}{\text{R}_1+\text{R}_2}$
$=\frac{1\times15}{10+15}=0.6\text{A}$
$\text{I}_2=\frac{\text{IR}_2}{\text{R}_1+\text{R}_2}$
$=\frac{1\times10}{10+15}=0.4\text{A}$
- p.d. across AB = IR3 = 1 × 5 = 5V
Equivalent resisyance between B and C is
$\frac{1}{\text{R}'}=\frac{1}{\text{R}_1}+\frac{1}{\text{R}_2}=\frac{1}{10}+\frac{1}{15}$
$\frac{1}{\text{R}'}=\frac{5}{30}$
R' = 6 ohm
Total resistance between A and C is R = 5 + 6 = 11 ohm
p.d. across AC = IR = 1 × 11 = 11V
- Total resistance = R3 + R' = 5 + 6 = 11 ohm.
