\(\therefore I_{1}=I_{2}\)
The potential difference between ends of galvanometer will be zero.
\(\therefore V_{A}-V_{B}=V_{A}-V_{D}\)
\(\therefore I_{1} R_{1}=\frac{q}{c_{1}} \ldots( i )\)
Similarly, \(V_{B}-V_{C}=V_{D}-V_{C}\)
\(I_{2} R_{2}=\frac{q}{c_{2}} \ldots( ii )\)
On dividing equation \((i)\) by equation \((ii)\), we get
\(\frac{I_{1} R_{1}}{I_{2} R_{2}}=\frac{q / C_{1}}{q / C_{2}}=\frac{C_{2}}{C_{1}}\)
\(\therefore \frac{C_{1}}{C_{2}}=\frac{R_{2}}{R_{1}}\)