In Young's double slit experiment, the '$\mathrm{n^{th}}' maximum of wavelength '\lambda_1' is at a distance '\mathrm{y_1}' from the central maximum. When the wavelength of the source is changed to '\lambda_2', \left(\frac{\mathrm{n}}{2}\right)^{\text {th }} maximum is at a distance of '\mathrm{y_2}' from its central maximum. The ratio \frac{y_1}{y_2}$ is