Question
If the refractive index from air to glass is $ \frac{3}{2} $ and that from air to water is $ \frac{4}{3} $, then the ratio of the focal lengths of a glass lens in water and in air is
If the refractive index from air to glass is $ \frac{3}{2} $ and that from air to water is $ \frac{4}{3} $, then the ratio of the focal lengths of a glass lens in water and in air is