lenses

• a convex lens causes rays of light to be brought together
• a concave lens caused the light rays to be spread out
• how do you draw a convex lens?

  • draw a ray going from the object to the lens parallel to the axis of the lens
  • draw another ray going through the middle of the lens
  • the first line is refracted through the principle focus
  • where the rays meet is where the image is
• how do you draw a concave lens?

  • draw a ray going from the object to the lens parallel to the axis of the lens
  • draw another ray going through the middle of the lens
  • the first ray is refracted so it appears to come from the principle focus so a dotted line is draw from that point
  • the image is where the lines meet
• concave waves always create virtual images
• by moving the object further than the focal point will, make the image appear bigger