Use Kirchhoff's rules to determine the potential differnce between the poits A and D when no current flows in the arm BE of the electric network shown in figure

Explanation

Since no current flows in the arm BE, so the current I flows along the outer loop as shown in figure
Using Kirchhoff's loop rule to the closed circuit AFEBA, we have
`2 I - 3 I + R_(1) xx 0-3 - 6=0`
or `5 I = 10 or I = 2A`
Potential difference across A to D while following the path AFD, we have
`V_(AD) = 2 xx 2 - 1 + 3xx2 = 9V`