There is a circular tube in a vertical plane . Two liquids which do not mix and of densities $\;d_{1}\;$ and $\;d_{2}\;$ are filled in the tube . Each liquid subtends $\;90^{0}\;$ angle at centre . Radius joining their interface makes an angle $\;\alpha\;$ with vertical . Ratio $\;\large\frac{d_{1}}{d_{2}}\;$ is :