question_answer

In the electrical network shown in the figure, the potential difference across \[3\,\Omega \] resistance will be

A)  12V                                      

B)  2.4V

C)  24V                      

D)         36V

Correct Answer: C

Solution :

As\[3\Omega \]and\[6\Omega \]resistances are in parallel their equivalent resistance will be\[2\Omega \]. Here\[2\Omega \]and \[4\Omega \]are in series, their equivalent resistance will be\[6\Omega \]. From current distribution law                 \[{{i}_{1}}=\frac{12\times 18}{18}=12\,\,A\]                 \[{{i}_{2}}=\frac{6\times 18}{18}=6A\] Now\[12\,\,A\]current is entering in parallel combination of\[3\Omega \]and\[6\Omega \]again from current distribution law                 \[i_{1}^{}=\frac{6\times 12}{9}=8\,\,A\]                 \[i_{2}^{}=\frac{3\times 12}{9}=4\,\,A\] \[\therefore \]Potential difference across \[3\Omega \] resistance                 \[=8\times 3=24\,\,V\]