6A20.50 • Concave and Convex Mirrors
Photo shows the demonstration used at the University of Texas at Austin.
Concepts Conveyed:
- Concave mirror:
- Focal Length = 68 cm
- When the object is outside the center of curvature (C), the image will be between C and focal point (F) and the image will be inverted and diminished.
- When the object is between C and F, the image will be beyond C and will be enlarged and inverted.
- When the object is between F and the mirror, the image will be behind the mirror and will be enlarged and upright.
- Convex mirror:
- Focal Length = -37 cm
- If the object is at infinity, the image will be a dot on the focal point. As the object moves from infinity toward the mirror, the image moves along the principal axis toward the mirror. When the object is right next to the mirror, the image will be right next to the mirror on the other side.
Instructions/Notes:
- Place the convex mirror on the mirror stand.
- Move around the object outside and inside of the focal length.
Last updated on March 5, 2026