1. Lenses and Mirrors
Working with Ray Diagrams

2. 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

3. 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

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

5. 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

6. 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

7. 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

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

9. 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

10. 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