Physics - Current Electricity Question with Solution | TestHub

By Kirchhoff's Current Law at junction B, the total current $I$ entering the section is the sum of the currents leaving.

$I=0.5\text{ A}+1.0\text{ A}+1.0\text{ A}=2.5\text{ A}$

The total resistance of the section AB is $R_{AB}=X+2\Omega$.

The power absorbed in the section AB is given by $P=I^2{R}_{AB}$.

Substituting the given values:

$50=(2.5{)}^2\times (X+2)$

$50=6.25\times (X+2)$

$X+2=\frac{50}{6.25}=8$

$X=8-2=6\Omega$

Answer: $6\Omega$