Question

What is the potential difference between the points $A$ and $B$ in the circuit diagram shown in figure?

• A. $\frac{20}{3}$ volt
• B. $\frac{10}{3}$ volt
• C. $\frac{20}{\sqrt{3}}$ volt
• D. $\frac{10}{\sqrt{3}}$ volt

Answer 1

Answer: (A)

$R_1+R_3=15\Omega ;R_2+R_4=12\Omega$
Let $R$ be the equivalent resistance between $A$ and $D$.
$\frac{1}{R}=\frac{1}{15}+\frac{1}{12}$
$R=\frac{15\times 12}{27}=\frac{20}{3}\Omega$
$I=\frac{20}{20/3}=3A$
$15I_1=12I_2$ or $I_1=\frac{4}{5}{I}_2$
$I_1+I_2=3A;I_1=\frac{4}{3}A;I_2=\frac{5}{3}A$
Potential difference between the points $A$ and $B$,
$V_A-V_B=5I_1=\frac{20}{3}\text{ volt }$