Light 2

  1. What are the two types of lenses?
    • Converging lens (Convex)
    • Diverging lens (Concave)
  2. What are converging lenses?
    • They are convex lenses.
    • They make parallel light rays converge/meet at a particular point.
    • The lens is thick in the middle and thin at the ends.
  3. What are diverging lenses?
    • They are concave lenses.
    • They make parallel light rays diverge after going through it.
    • The lens is thin in the middle and thick at the ends.
  4. Images formed by converging lenses
    • As long as the object is outside the focal point, the image is real and inverted.
    • When the object is inside the focal point, the image is virtual and upright.
    • When the object is at 2F, the image formed is the same size as the object.
  5. List down formulas to find Linear magnification, m
    Image Upload 2


    Image Upload 4
  6. How are images formed in our eye?
    • Light falling on object is reflected in all directions.
    • Some reflected rays enter the eye.
    • These light rays are bent (refracted) by the cornea, vitrous humor, lens, etc.
    • Bent light rays meet on the retina.
    • An inverted image is formed.
    • Images on retina creates impulses, which will travel to the brain by sensory neurones.
    • Brain interprets impulses so that the viewer sees the object right way up.
  7. Name the two types of eye defects.
    • Long-sight - can see far objects clearly, but near objects appear blur. (corrected by converging lens)
    • Short-sight - can see near objects clearly, but far objects appear blur. (corrected by diverging lens)
  8. Accommodation
    • Changes of lens shape
    • When I try to focus on a distant object, my lens become thin
    • When I try to focus on a nearby object, my lens become fat
Card Set
Light 2
Lenses, application to eye, etc