Lenses and Mirrors Working with Ray Diagrams

Convex Lens Real Image do di Image Object f Image is real, inverted & diminished Image Object f A ray through f1 is refracted parallel to the axis A ray parallel to the axis is refracted through f2 Two focal points - f1 on left, f2 on right A ray through the center of the lens passes through the lens unrefracted

Convex Lens Sample Problem: Find the focal length of the lens. 1/f = 1/di + 1/do 1/f = 1/24 cm + 1/48 cm 1/f = 2/48 cm + 1/48 cm 1/f = 3/48 cm = 1/16 cm f = 16 cm

Convex Lens Real Image do di Image is real, inverted & enlarged f

Convex Lens Virtual Image do f di Image is virtual, erect & enlarged A ray parallel to the axis is refracted through f2 A ray through the center of the lens passes through the lens unrefracted Extend the rays backward with dashed lines Where the dashed lines meet is where the image is formed

Concave Lens Virtual Image f do di Image is virtual, erect & diminished A ray through the center of the lens passes through the lens unrefracted Two focal points - f2 on left, f1 on right (opposite of convex lens!) A ray toward f1 is refracted parallel to the axis A ray parallel to the axis is refracted away from f2 Where these rays intersect is the image Extend the rays backward with dashed lines

Concave Mirror Real Image do f di Image is real, inverted & diminished A ray through the center of curvature is reflected back on itself A ray parallel to the axis is reflected through the focal point Two points: Focal Point f and Center of Curvature (2f) A ray through the focal point is reflected parallel to the axis

Concave Mirror Real Image do f di Image is real, inverted & enlarged Object located between Focal Point and C.O.C. – same rules apply

Concave Mirror Virtual Image do di Image is virtual, erect & enlarged Where they intersect is the image!! Extend the reflected rays with dashed lines A ray parallel to the axis is reflected through the focal point A ray from the center of curvature is reflected back on itself A ray from the focal point is reflected parallel to the axis

Convex Mirror Virtual Image do di Image is virtual, erect & diminished Extend the reflected rays with dashed lines A ray toward the center of curvature is reflected back on itself Where the extensions meet is the image location!! A ray parallel to the axis is reflected away from the focal point f and C are located on the opposite side of the mirror A ray toward the focal point is reflected parallel to the axis