The redius of curvature of the convex face of a plano-convex lens is 12cm and its refractive index is 1.5. a. Find the focal length of this lens. The

The redius of curvature of the convex face of a plano-convex lens is 12cm and its refractive index is 1.5.
a. Find the focal length of this lens. The plane surface of the lens is now silvered.
b. At what distance form the lans will parallel rays incident on the convex face converge?
c. Sketch the ray diagram to locate the image, when a point object is places on the axis 20cm from the lens.
d. Calculate the image distance when the object is placed as in (c).