OMTEX CLASSES: Explain the sign conventions for reflection by spherical mirrors.

Explain the sign conventions for reflection by spherical mirrors.



According to the new Cartesian sign convention, the pole (P) of the mirror is taken as origin. The principal axis is taken as X-axis of the co-ordinate system. The sign conventions are as follows:



1.       The object is always placed on the left of the mirror.
2.       All distances parallel to principal axis are measured from the pole of the mirror.
3.       All the distances measured to the right of the origin are taken as positive, while distances measured to the left of the origin are taken as negative.
4.       Distances measured perpendicular to and above the principal axis are taken as positive.
5.       Distances measured perpendicular to and below the principal axis are taken as negative.

6.       Focal length of convex mirror is positive while that of concave mirror is negative.