Question

What is the new Cartesian sign convention of concave and convex Lens?

Answer 1

Sign convention:

1. Focal length of a convex lens is positive.
2. Whereas focal length of a concave lens is negative, according to the sign convention. Because the object is always on the lens's left side, the incident light always moves from left to right.
3. All distances measured from the lens's optical center to the right side are considered positive.
4. Distances measured in the opposite direction of the incident light are considered negative.
5. Positive distances are those measured in the same direction as the incident light.
6. Positive heights are those measured upwards and perpendicular to the principal axis.
7. Negative heights are those measured downwards and perpendicular to the principal axis.