In the given circuit, which is a part of closed circuit, find the currents  

Let the potential at O be V
From Kirchoff’s junction law
${\text{i = i}}_1+{\text{i}}_{\text{2}}$
$\frac{30-\text{V}}{10}=\frac{\text{V}-12}{20}+\frac{\text{V}-2}{30}$
180 – 6V = 5V – 40
11V = 220
V = 20 volt
${\text{i}}_1=\frac{\text{V}-12}{20}=\frac{8}{20}=0.4\text{\hspace{0.17em}A}$
${\text{i}}_2=\frac{18}{30}=0.6\text{\hspace{0.17em}A}$