j.m. gabrielse ray diagrams. j.m. gabrielse outline reflection mirrors plane mirrors spherical...

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  • Slide 1
  • J.M. Gabrielse Ray Diagrams
  • Slide 2
  • J.M. Gabrielse Outline Reflection Mirrors Plane mirrors Spherical mirrors Concave mirrors Convex mirrors Refraction Lenses Concave lenses Convex lenses
  • Slide 3
  • J.M. Gabrielse A ray of light is an extremely narrow beam of light.
  • Slide 4
  • J.M. Gabrielse All visible objects emit or reflect light rays in all directions.
  • Slide 5
  • J.M. Gabrielse Our eyes detect light rays.
  • Slide 6
  • J.M. Gabrielse We see images when light rays converge in our eyes. converge: come together
  • Slide 7
  • J.M. Gabrielse Mirrors object image It is possible to see images in mirrors.
  • Slide 8
  • J.M. Gabrielse Reflection (bouncing light) Reflection is when light changes direction by bouncing off a surface. When light is reflected off a mirror, it hits the mirror at the same angle (the incidence angle, i ) as it reflects off the mirror (the reflection angle, r ). The normal is an imaginary line which lies at right angles to the mirror where the ray hits it. rr ii Mirror normal incident ray reflected ray
  • Slide 9
  • J.M. Gabrielse Mirrors reflect light rays.
  • Slide 10
  • J.M. Gabrielse Plane Mirrors (flat mirrors) How do we see images in mirrors?
  • Slide 11
  • J.M. Gabrielse Plane Mirrors (flat mirrors) objectimage Light reflected off the mirror converges to form an image in the eye. How do we see images in mirrors?
  • Slide 12
  • J.M. Gabrielse Plane Mirrors (flat mirrors) objectimage Light reflected off the mirror converges to form an image in the eye. The eye perceives light rays as if they came through the mirror. Imaginary light rays extended behind mirrors are called sight lines. How do we see images in mirrors?
  • Slide 13
  • J.M. Gabrielse Plane Mirrors (flat mirrors) objectimage Light reflected off the mirror converges to form an image in the eye. The eye perceives light rays as if they came through the mirror. Imaginary light rays extended behind mirrors are called sight lines. The image is virtual since it is formed by imaginary sight lines, not real light rays. How do we see images in mirrors?
  • Slide 14
  • J.M. Gabrielse Spherical Mirrors (concave & convex)
  • Slide 15
  • J.M. Gabrielse Concave & Convex (just a part of a sphere) C: the center point of the sphere r: radius of curvature (just the radius of the sphere) F: the focal point of the mirror (halfway between C and the mirror) f: the focal distance, f = r/2 r f C F
  • Slide 16
  • J.M. Gabrielse optical axis Concave Mirrors (caved in) F Light rays that come in parallel to the optical axis reflect through the focal point.
  • Slide 17
  • J.M. Gabrielse optical axis Concave Mirror (example) F
  • Slide 18
  • J.M. Gabrielse optical axis Concave Mirror (example) F The first ray comes in parallel to the optical axis and reflects through the focal point.
  • Slide 19
  • J.M. Gabrielse optical axis Concave Mirror (example) F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis.
  • Slide 20
  • J.M. Gabrielse optical axis Concave Mirror (example) F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis. A real image forms where the light rays converge.
  • Slide 21
  • J.M. Gabrielse optical axis Concave Mirror (example 2) F
  • Slide 22
  • J.M. Gabrielse optical axis Concave Mirror (example 2) F The first ray comes in parallel to the optical axis and reflects through the focal point.
  • Slide 23
  • J.M. Gabrielse optical axis Concave Mirror (example 2) F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis.
  • Slide 24
  • J.M. Gabrielse optical axis Concave Mirror (example 2) F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis. The image forms where the rays converge. But they dont seem to converge.
  • Slide 25
  • J.M. Gabrielse optical axis Concave Mirror (example 2) F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis. A virtual image forms where the sight rays converge.
  • Slide 26
  • J.M. Gabrielse optical axis Your Turn (Concave Mirror) F object concave mirror Note: mirrors are thin enough that you just draw a line to represent the mirror Locate the image of the arrow
  • Slide 27
  • J.M. Gabrielse optical axis Your Turn (Concave Mirror) F object concave mirror Note: mirrors are thin enough that you just draw a line to represent the mirror Locate the image of the arrow
  • Slide 28
  • J.M. Gabrielse Convex Mirrors (curved out) Light rays that come in parallel to the optical axis reflect from the focal point. optical axis F The focal point is considered virtual since sight lines, not light rays, go through it.
  • Slide 29
  • J.M. Gabrielse Convex Mirror (example) optical axis F
  • Slide 30
  • J.M. Gabrielse Convex Mirror (example) optical axis F The first ray comes in parallel to the optical axis and reflects through the focal point.
  • Slide 31
  • J.M. Gabrielse Convex Mirror (example) optical axis F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis.
  • Slide 32
  • J.M. Gabrielse Convex Mirror (example) optical axis F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis. The light rays dont converge, but the sight lines do.
  • Slide 33
  • J.M. Gabrielse Convex Mirror (example) optical axis F The first ray comes in parallel to the optical axis and reflects through the focal point. The second ray comes through the focal point and reflects parallel to the optical axis. The light rays dont converge, but the sight lines do. A virtual image forms where the sight lines converge.
  • Slide 34
  • J.M. Gabrielse optical axis Your Turn (Convex Mirror) F Note: mirrors are thin enough that you just draw a line to represent the mirror Locate the image of the arrow object convex mirror
  • Slide 35
  • J.M. Gabrielse optical axis Your Turn (Convex Mirror) F Note: mirrors are thin enough that you just draw a line to represent the mirror Locate the image of the arrow object convex mirror image
  • Slide 36
  • J.M. Gabrielse Lensmakers Equation = focal length d o = object distance d i = image distance if distance is negative the image is behind the mirror
  • Slide 37
  • J.M. Gabrielse Magnification Equation m = magnification h i = image height h o = object height If height is negative the image is upside down if the magnification is negative the image is inverted (upside down)
  • Slide 38
  • J.M. Gabrielse Refraction (bending light) Refraction is when light bends as it passes from one medium into another. When light traveling through air passes into the glass block it is refracted towards the normal. When light passes back out of the glass into the air, it is refracted away from the normal. Since light refracts when it changes mediums it can be aimed. Lenses are shaped so light is aimed at a focal point. normal air rr ii rr ii glass block
  • Slide 39
  • J.M. Gabrielse Lenses The first telescope, designed and built by Galileo, used lenses to focus light from faraway objects, into Galileos eye. His telescope consisted of a concave lens and a convex lens. Light rays are always refracted (bent) towards the thickest part of the lens. convex lens concave lens light from object
  • Slide 40
  • J.M. Gabrielse Concave Lenses Concave lenses are thin in the middle and make light rays diverge (spread out). If the rays of light are traced back (dotted sight lines), they all intersect at the focal point (F) behind the lens. optical axis F
  • Slide 41
  • J.M. Gabrielse F optical axis Light rays that come in parallel to the optical axis diverge from the focal point. Concave Lenses The light rays behave the same way if we ignore the thickness of the lens.
  • Slide 42
  • J.M. Gabrielse Concave Lenses optical axis F Light rays that come in parallel to the optical axis still diverge from the focal point.
  • Slide 43
  • J.M. Gabrielse Concave Lens (example) The first ray comes in parallel to the optical axis and refracts from the focal point. optical axis F
  • Slide 44
  • J.M. Gabrielse Concave Lens (example) optical axis F The

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