Question

In the circuit diagram, potential difference between points $A$ and $B$ is $200 \,V$, the potential difference between points $a$ and $b$ when the switch $S$ is open, is

• A. 100 V
• B. $\frac{200}{3} \,V$
• C. $\frac{100}{3} \,V$
• D. 50 V

Answer 1

Answer: (B)

$V_{A}-V_{a}=\frac{200 \times 6}{3+6}$
$=\frac{200 \times 6}{9} V =\frac{400}{3} V$
$V_{A}-V_{b}=\frac{200 \times 3}{3+6}$
$=\frac{200 \times 3}{9} V =\frac{200}{3} V$
$V_{A}-V_{a}-\left(V_{A}-V_{b}\right)$
$=V_{b}-V_{a}=\frac{200}{3} V$