Physics - Current Electricity Question with Solution | TestHub

Let when link AB is removed, $x$ is an equivalent of remaining part of cube without link. AB and rest part will be in paralel, so according to question $$\begin{array}{c}\frac{7}{12}=\frac{R_1{R}_2}{R_1+R}=\frac{1(x)}{1+x}=\frac{x}{1+x}\\ \frac{7}{12}=\frac{x}{1+x}\\ 12x=7+7x\\ 12x-7x=7\end{array}5x=7$$ $$x=\frac{7}{5}\Omega$$