Sign convention for spherical lenses
Sign convention for spherical lenses Sign convention of spherical lens is similar to the sign convention of the spherical mirrors. Object is placed on the left of the lens. It means to say that light must passes through the lens from left to light. All measurements of distance are taken from the optical centre of the lens. The focal length of a convex lens is positive. And the focal length of the concave lens is negative. All distance measured above the principal axis are positive. All distance measured below the principal axis are negative. All the distance measured in the direction of incident rays are positive. All the distance measured in the direction opposite to that of the incident rays are negative. Lens formula and magnification Lens formula provides the relationship between object distance (u) , image distance (v) and the focal length (f). lens formula is applicable of both concave lens ...