Thank you for reporting, we will resolve it shortly
Q.
The effective resistance between points $A$ and $B$ is
Current Electricity
Solution:
Here points $B$ and $D$ are common.
So, $2 R$ in arm $D C$ and $2 R$ in arm $C B$ are in parallel between $C$ and $B$.
Their effective resistance $=\frac{2 R \times 2 R}{2 R+2\,R}=R$
The modified and simpler circuit will be shown in figure. The effective resistance between $A$ and $B$ is
$R_{\text {eff }}=\frac{R \times(R+R)}{R+(R+R)}=\frac{2}{3} R$
