Question

distance perpendicular to principal axis and above it are taken to be ​

Answer 1

Answer:

(ii) All distances parallel to the principal axis are measured from the pole of the mirror. ... (iv) Distances measured perpendicular to and above the principal axis (along + y-axis) are taken as positive. (v) Distances measured perpendicular to and below the principal axis (along –y-axis) are taken as negative.