Question

The equivalent resistance between $A$ and $B$ for the circuit shown in figure is

• A. $13.1\Omega$
• B. $15.1\Omega$
• C. $17.1\Omega$
• D. $19.1\Omega$

Answer 1

Answer: (A)

For equivalent resistance between $A$ and $B$. $5\Omega$ and $8\Omega$ resistances are connected in series. $R$', their equivalent resistance is parallel to $6\Omega$
$\therefore R^{\prime }=5+8=13\Omega$ and $\frac{1}{R^{\prime \prime }}=\frac{1}{13}+\frac{1}{6}$
$=\frac{6+13}{78}=\frac{19}{78}$
$R^{\prime \prime }=\frac{78}{19}$
Now $4\Omega$, $R$'' and $5\Omega$ resistances are connected in series equivalent resistance between $A$ and $B$.
$\therefore R_{eq}=4+\frac{78}{19}+5$
$=\frac{76+78+95}{19}=13.1\Omega$