week 10

• Leonardo da Vinci


  Designed the first contact lens in 1508, wearing a water-filled glass hemisphere over the eye
• Rene Descartes


  Proposed a glass tube to be worn directly on the cornea
• Mirror


  A reflective surface that bounces off light, producing either a real image or a virtual image. Can be plane or curved mirror
• Virtual image


  Formed when light from a single source spreads out or diverges after passing through a lens or after being reflected
• Real image


  Formed when the rays from the reflection of light meet or converge at a single point on the other side of the lens
• Terms used in the study of spherical mirrors

  • Center of curvature
  • Radius of curvature
  • Pole
  • Principal axis
  • Principal focus (concave)
  • Principal focus (convex)
  • Focal length
• Principal focus (concave)


  • Rays of light parallel to the principal axis after reflection meet at a point on the principal axis
• Principal focus (convex)


  • Rays of light parallel to the principal axis after reflection get diverged and appear to come from a point on the principal axis behind the mirror
• Uses of concave mirrors

  • Dental mirrors
  • Shaving mirror
  • Headlight car
  • Reflector
• Uses of convex mirrors

  • Rear-view mirrors in vehicles
  • Convex security mirror
• Lens


  Made up of transparent material such as glass or plastic with a refractive index larger than that of air, plays a vital role in the study of the behavior of light
• Types of spherical lenses

  • Concave lenses
  • Convex lenses
• Meniscus lens


  Lenses that are produced when concave and convex lenses are combined, has convex and concave lenses on both sides
• Uses of convex lenses

  • Camera lens
  • Telescope
  • Magnifying
  • Glasses (for hypermetropia)
• Uses of concave lenses

  • Peepholes
  • Flashlight
  • Glasses (for myopia)
  • Cameras
• Microscope


  An instrument that is used in viewing small objects and microorganisms that are impossible for our unaided eyes to see, uses lenses that can magnify objects 100x or even more than a thousand times