Today 2/6  Lenses--Ray Diagrams and Math  Lab: Any Questions?  HW Questions?  Start reading chapter on Lenses  HW:2/6 Text Problem Ch 26 #55 Due Monday, 2/10  Exam IThursday, Feb 13

Converging Lens-Ray Diagrams ff Bend the ray at the middle of the lens In parallel-out through focus Also straight through the center of the lens d i image distance d 0 object distance The image will also appear on a screen placed at the image location. h0h0 hihi In through focus-out parallel

Equations Thin lens equation Magnification equation f focal length always + for converging lens (- for diverging) d 0 object distance + if on input side d i image distance + if output side (- if on input side) m magnification + if image is (- if image inverted) h height + if not inverted (- if inverted)

Converging Lens-Ray Diagrams ff d i image distance d 0 object distance The image will also appear on a screen placed at the image location. h0h0 hihi f = +4cm d 0 = +12cm d i = +6cm h 0 = +2cm h i = -1cm m = -0.5 (no units)

Converging Lens-Ray Diagrams ff Bend the ray at the middle of the lens In from focus-out parallel Also straight through the center of the lens d 0 object distance image distance d i Now we have to “backtrack” the rays to see where they seem to come from! In parallel-out through focus

Converging Lens-Ray Diagrams ff d 0 object distance image distance d i Now we have to “backtrack” the rays to see where they seem to come from! f = +4cm d 0 = +2cm d i = -4cm h 0 = +1cm h i = +2cm m = +2 (no units)