A thin convex lens of focal length 20cm is placed on its principal axis. An object is kept 30cm in front of the lens.
(i) Calculate the distance of the image from the lens.
(ii) Determine the magnification produced and state whether the image is erect or inverted, enlarged or diminished.
(iii) If the object height is 4cm, find the height of the image giving its proper sign and unit.