Question

The resistance of a conductor is 1.08$\Omega$. To reduce it to 1$\Omega$, the resistance that must be connected is:

• A. $0.08$ $\Omega$ in series
• B. $13.5$ $\Omega$ is parallel
• C. $0.08$ $\Omega$ in parallel
• D. $13.5$ $\Omega$ in series.

Answer 1

Answer: (B)

$13.5$ $\Omega$ is parallel

To reduce the resistance value we should connect another resistance in parallel.
So, $R=\frac{R_1{R}_2}{R_1+R_2}$
or, $1=\frac{1.08\times R_2}{1.08+R_2}$
or, $1.08+R_2=1.08R_2$
or, $1.08=0.08R_2$
$\therefore$ $R_2=\frac{108}{8}=13.5\Omega$