Lens Types and Image Formation

Converging (Convex) Lenses

• Converging lenses cause parallel rays of light to converge.
• The point where the light converges is called the principal focus or focal point (F) of the lens.
• Focal Length: the distance from the center of the lens to the principle focus

Diverging (Concave) Lenses

• Diverging lenses cause parallel rays of light to diverge.
• The rays diverge away from the principal focus (or focal point) of the lens.
• Focal Length: the distance from the center of the lens to the principle focus

Image Formation

• Real Image (Converging Lens):
  • A real image is formed by a converging lens when the object is located beyond the principal focus.
• Virtual Image (Converging Lens):
  • A virtual image is formed by a converging lens when the object is closer than the principal focus.
• Virtual Image (Diverging Lens):
  • A diverging lens always forms a virtual image.