State and explain the New Cartesian Sign Convention for spherical lenses.

New Cartesian Sign Convention is used for measuring the distance in the ray diagram of lenses.

The conventions are:

All the distances from of the object or its image is measured from the optical center.

The distance measured in the direction of incidence light are always taken as positive.

The distance measured opposite to the direction of the incident light are taken as negative.

The distance measured in the upwards direction is taken as positive.

The distance measured in the downward direction is taken as negative.

New Cartesian Sign Convention is used for measuring the distance in the ray diagram of lenses.