Theory:

To measure distances in the ray diagram, we use a set of sign conventions known as the cartesian coordinate sign convention. The pole of the spherical mirror (\(P\)) is considered as the origin in this convention. The principal axis is taken as the X-axis of the coordinate system.
  • The object should always be positioned on the mirror's left side.
  • All distances are calculated from the mirror's pole.
  • Positive distances are measured in the direction of the incident light, while negative distances are measured in the opposite direction.
  • Positive distances are those that are measured perpendicular to and above the principal axis.
  • Negative distances are those that are measured perpendicular to and below the principal axis.
22 (2).png
Sign convention for spherical mirrors
  
The below table shows the sign convention,
21 (2).png
Sign convention for spherical mirrors