Consider a lens of thickness 1 cm, made of a material oft refractive index 1.5, placed in air. the radii of curvature of the first and second surfaces are +4 cm

Consider a lens of thickness 1 cm, made of a material oft refractive index 1.5, placed in air. The radii of curvature of the first and second surfaces are +4 cm and 4 cm, respec- tively. Determine the point at which parallel rays will will focus. [Ans: At a distance of about 4.55 cm from the second surface.]