How do lenses work? How do they form images? Well, in order to understand how optics work, we have to understand the physics of light. In this episode of Crash Course Physics, Shini talks to us about optical instruments and how they make...

It explains two types of spherical lenses; convex and concave lenses. It also explains technical terms related to them.It also describes the converging property of convex lens and diverging property of concave lens.

It about the optical devices-the eye, telescope, image beyond 2F length, image at infinity and telescope.