Describe the New Cartesian Sign Convention used in optics. Draw a labelled diagram to illustrate this sign convention.

According to the new cartesian sign convention used in optics :

1. All distances are measured from the pole of the mirror as origin.

2. Distances measured in the same direction as that of incident light are taken as positive.

3. Distances measured against the direction of incident light are taken as negative.

4. Distances measured upward and perpendicular to the principal axis are taken as positive.

5. Distances measured downward and perpendicular to the principal axis are taken as negative.