Question

Find out the value of resistance $R$ in figure.

• A. $100\Omega$
• B. $150\Omega$
• C. $500\Omega$
• D. $200\Omega$

Answer 1

The correct option is A $100\Omega$


From the figure, we can see that potential difference across $\text{C}$ and $\text{D}$ is $100\text{V}$.

Hence, $I_1=\frac{100}{100}=1\text{A}$

$V_{AC}=120-100=20\text{V}$

Also, $I=\frac{20}{10}=2\text{A}$

Hence, $I_2=2-1=1\text{A}$

$\therefore R=\frac{V}{I}=\frac{100}{1}=100\Omega$

Hence, option $\left(a\right)$ is correct.