Question

In the circuit shown the cells A and B have negligible resistances. For $V _{ A }=10\, V,\, R _{1}=300\, \Omega$ and $R =200\, \Omega$ the galvanometer $(G)$ shows no deflection. The value of $V_{B}$ is :-

• A. 12 V
• B. 6 V
• C. 4 V
• D. 2 V

Answer 1

Answer: (C)

$V_{B}=$ Voltage Across $R$
$\Rightarrow V_{B}=\frac{V_{A}}{R_{1}+R} \cdot R$
$=\frac{10}{300+200} \cdot 200$
$\Rightarrow V_{R}=\frac{10}{5} \times 2=4\, V$