Question

Which of the following statements is/are NOT true according to the sign convention for spherical lenses?
(i) All distances parallel to the principal axis are measured from the focus of the lens.
(ii) All the distances measured to the right of the origin are taken as positive.
(iii) Distances measured perpendicular to and above the principal axis are taken as negative.
(iv) The object is always placed to the left of the lens.