Find out the Relation between `C_1, C_2, C_3 and C_4` such that point A and B are equipotential. [Balanced wheat stone bridge]

Explanation

When A and B are equipotential then there will be no charge on capacitor `C_5.` So remove it. Now `C_1, C_2` are in series and `C_3, C_4` are in series so they will have same charges respectively.
`rArr q_(1)/C_(1)=q_(2)/C_(3) .......(1)`

and `q_(1)/C_(2)=q_(2)/C_(4) ..........(2)`
`C_(2)/C_(1)=C_(4)/C_(3) rArr C_(2)C_(3)=C_(1)C_(4)`