# Fun with optics!

Water (with refractive index $$\frac43$$ ) in a tank is 18 cm. Oil of refractive index $$\frac74$$ lies on water making a convex surface of radius of curvature $$R = 6\text{ cm}$$. Consider oil to act as a thin lens. An object $$S$$ is placed $$24\text{ cm}$$ above water surface. The location of its image is at $$X \text{ cm}$$ above the bottom of the tank. What is the value of $$X$$?

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