Question

With the help of appropriate ray diagram, state the sign conventions for reflection by spherical mirror.

Answer 1

Sign convention : According to the new Cartesian sign convention, the pole (P) of the mirror is taken as the origin. The principal axis is taken as X-axis of the coordinate system. The sign conventions are as follows:
(a) The object is always placed on the left of the mirror.
(b) All distance parallel to principal axis are measured from the pole of the mirror.
(c) All the distances measured to the right of the origin are taken as positive, while distance measured to the left of the origin are taken as negative.
(d) Distances measured to the perpendicular to and below the principal axis are taken as negative.
(e) Distances measured perpendicular to above and above the principle axis are taken as positive.
(f)The focal length of the convex mirror is positive while that of the concave mirror is negative.