Problem 1: A thin hollow glass sphere has a radius of 1 m. A coin is placed at the bottom of the glass sphere. 2.09 metre cube of a liquid of refractive index 1.5 is poured into the glass shpere. A person is viewing the object vertically. What is the apparent depth of the coin? Im not sure if there will be refraction at the glass surface and i dont know how to consider it. I need help. Problem 2: A convex lens has a thickness 0.2m. The radii of curvature of the two surfaces are 1 and 2 m respectively. An object is kept at a distance of 10m from the left surface. The right surface is silvered. Find the position of final image. I considered refraction at surface 1 , refration at surface 2, then reflection and then again refraction at surface 2 and refration at surface 1. Is that right?