Question

Two resistors of resistances $R_1$ = (300 $\pm$ 3) $\Omega$ and $R_2$ = (500 $\pm$ 4) $\Omega$ are connected in series. The equivalent resistance of the series combination is

• A. (800 $\pm$ 1) $\Omega$
• B. (800 $\pm$ 7) $\Omega$
• C. (200 $\pm$ 7) $\Omega$
• D. (200 $\pm$ 1) $\Omega$

Answer 1

The correct option is B (800 $\pm$ 7) $\Omega$

The equivalent resistance of series combination is
$R_s=R_1+R_2=300\Omega +500\Omega =800\Omega$
The error in equivalent resistance is given by
$\Delta R=(\Delta R_1+\Delta R_2)=(3+4)\Omega =7\Omega$
Hence, the equivalent resistance along with error is $(800\pm 7)\Omega$.