Question

In the given circuit diagram the ratio of potential difference across $3$ ohm and $4$ ohm resistance is $\frac{3}{4}$. The unknown resistance $R$ is:-

• A. $\text{8.0 ohm}$
• B. $\text{2.0 ohm}$
• C. $\text{4.5 ohm}$
• D. $\text{7.0 ohm}$

Answer 1

The correct option is A $\text{8.0 ohm}$

Potential difference across $=3\Omega$ $4\Omega$

resistance $=\frac{3}{4}$

Using wheat stone bridge method we get,

$\frac{5}{6}=\frac{4}{R}$

or, $R=\frac{4\times 6}{5}=\frac{24}{5}=\frac{40}{5}=8\Omega$