A thick lens is placed at the end of a fish tank containing a Transparent liquid whose refractive index is 1.420. The lens has surfaces of radii of curvature of R1 = +3.80 cm and R2 = ?1.90 cm, a thickness of 4.60 cm and is made of a glass whose index of refraction is 1.620. If R2 is in contact with the liquid, obtain (a) the front and back focal lengths, (b) the power of the lens. (c) Obtain also the distances from the vertices to the foci and to the respective main planes.