The video tutorial explains the characteristics of images formed by spherical lenses, focusing on the use of ray diagrams and numerical methods. It introduces the Cartesian sign convention for lenses, where distances along the direction of incident light are positive. The lens formula, 1/v - 1/u = 1/f, is discussed, applicable to both concave and convex lenses. Magnification is defined as the ratio of image height to object height, with m = -v/u. The video also covers optical power, defined as the inverse of focal length, measured in diopters. The power of convex lenses is positive, while concave lenses have negative power. The tutorial concludes with a recap of these concepts.

What is magnification, and how is it calculated in relation to object and image height?

Define optical power of a lens and explain how it is related to focal length.

What happens to the effective power when multiple lenses are used in combination?