Refraction is the change in direction of light when it passes from one medium to another. The working of a lens is based on the refraction of light when they pass through it. Lens is a transparent ...
In a ray diagram, a concave lens is drawn as a vertical line with inward facing arrows to indicate the shape of the lens.
Light travels at different speeds based on the medium it passes through. For example, in a vacuum, it travels at 3.0 × 10^8 m/s in a straight line. But when directed towards glass, air, diamond, water ...