Optical devices that transmits and refracts light
Our eye has lens behind pupils
There are 2 basic lens shapes, converging and diverging.
Parallel light rays diverge after refraction from the lens
This lens is thickest at the edges and thinnest in middle
Parallel light rays diverge after refraction from the lens
This lens is thickest at the edges and thinnest in middle
Note:
light rays refract twice: entering lens and exiting lens.
Direction of light →
Actual path of light shows 2 refractions in lens
Light always cross focal point
Ray diagrams are drawn with only 1 refraction.
From a vertical line through middle of lens.
Note: Light rays refract twice: entering the lens and exiting the lens.
Parallel lights rays converge at the principal focus (F) after refracting through this lens is thicket in middle and thinnest at the edges.
As long object is outside of focal point, image: always real and inverted
Only when inside focal point image becomes: virtual and upright
Convex lens have 2 spherical faces. Each of them forms a part of a sphere.
The centers of these spheres called "Center of Curvature" of the lens. Since there are 2 center. We represent as C1 and C2 👇
As mentioned, the principal axis is an imaginary line passing 2 centers of curvatures C1 ad C2 of lens.
Diagrams in lenses have 4 focus poits in total (2 on each sides), unlike mirrors, which 1.