OpticsMirrors and Lenses

ReflectionWe describe the path of light as straight-line raysReflection off a flat surface follows a simple rule:angle in (incidence) equals angle out (reflection)angles measured from surface normal (perpendicular)incident rayexit ray reflected ray

Reflection VocabularyReal Image Image is made from real light rays that converge at a real focal point so the image is REALCan be projected onto a screen because light actually passes through the point where the image appearsAlways inverted

UCSD: Physics 8; 2006

Reflection VocabularyVirtual Image Not Real because it cannot be projected Image only seems to be there!

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Virtual Images in Plane Mirrors

If light energy doesn't flow from the image,the image is "virtual".

Rays seem to come from behind the mirror, but, of course, they don't. It is virtually as if the rays were coming from behind the mirror. "Virtually": the same as if As far as the eye-brain system is concerned, the effect is the same as would occur if the mirror were absent and the chess piece were actually located at the spot labeled "virtual image".

Hall MirrorUseful to think in terms of imagesmirror onlyneeds to be half ashigh as you are tall. Yourimage will be twice as far from youas the mirror.

LEFT- RIGHT REVERSAL

Curved mirrorsWhat if the mirror isnt flat?light still follows the same rules, with local surface normalParabolic mirrors have exact focusused in telescopes, backyard satellite dishes, etc.also forms virtual image

Concave MirrorsCurves inwardMay be real or virtual imageView kacleaveland's map

Taken in a place with no name (See more photos or videos here)

"Have you ever approached a giant concave mirror? See your upside-down image suspended in mid-air. Walk through the image to see a new reflection, right-side-up and greatly magnified. In the background you see reflected a room full of visitors enjoying other

UCSD: Physics 8; 2006

For a real object between f and the mirror, a virtual image is formed behind the mirror. The image is upright and larger than the object.

For a real object between f and the mirror, a virtual image is formed behind the mirror. The position of the image is found by tracing the reflected rays back behind the mirror to where they meet. The image is upright and larger than the object.

For a real object between f and the mirror, a virtual image is formed behind the mirror. The position of the image is found by tracing the reflected rays back behind the mirror to where they meet. The image is upright and larger than the object.

For a real object close to the mirror but outside of the center of curvature, the real image is formed between C and f. The image is inverted and smaller than the object.

For a real object between C and f, a real image is formed outside of C. The image is inverted and larger than the object. For a real object between C and f, a real image is formed outside of C. The image is inverted and larger than the object.

For a real object between f and the mirror, a virtual image is formed behind the mirror. The position of the image is found by tracing the reflected rays back behind the mirror to where they meet. The image is upright and larger than the object.

For a real object close to the mirror but outside of the center of curvature, the real image is formed between C and f. The image is inverted and smaller than the object.

For a real object between C and f, a real image is formed outside of C. The image is inverted and larger than the object.

For a real object at C, the real image is formed at C. The image is inverted and the same size as the object.

For a real object at C, the real image is formed at C. The image is inverted and the same size as the object.

For a real object between f and the mirror, a virtual image is formed behind the mirror. The position of the image is found by tracing the reflected rays back behind the mirror to where they meet. The image is upright and larger than the object.

For a real object close to the mirror but outside of the center of curvature, the real image is formed between C and f. The image is inverted and smaller than the object.

For a real object close to the mirror but outside of the center of curvature, the real image is formed between C and f. The image is inverted and smaller than the object.

For a real object at f, no image is formed. The reflected rays are parallel and never converge.

For a real object at f, no image is formed. The reflected rays are parallel and never converge. What size image is formed if the real object is placed at the focal point f?

Convex Mirrors

Curves outwardReduces imagesVirtual imagesUse: Rear view mirrors, store securityCAUTION! Objects are closer than they appear!

UCSD: Physics 8; 2006

RefractionLight also goes through some thingsglass, water, eyeball, airThe presence of material slows lights progressinteractions with electrical properties of atomsThe light slowing factor is called the index of refractionglass has n = 1.52, meaning that light travels about 1.5 times slower in glass than in vacuumwater has n = 1.33air has n = 1.00028vacuum is n = 1.00000 (speed of light at full capacity)

Refraction at a plane surfaceLight bends at interface between refractive indicesbends more the larger the difference in refractive index

Convex Lenses Thicker in the center than edges. Lens that converges (brings together) light rays. Forms real images and virtual images depending on position of the objectThe Magnifier

UCSD: Physics 8; 2006

Concave LensesLenses that are thicker at the edges and thinner in the center. Diverges light rays All images are erect and reduced.The De-Magnifier

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How You See Near Sighted Eyeball is too long and image focuses in front of the retinaNear Sightedness Concave lenses expand focal lengthFar Sighted Eyeball is too short so image is focused behind the retina.Far Sightedness Convex lense shortens the focal length.

UCSD: Physics 8; 2006

Cameras, in briefIn a pinhole camera, the hole is so small that light hitting any particular pointon the film plane must have come from a particular direction outside the cameraIn a camera with a lens, the same applies: that a point on the film planemore-or-less corresponds to a direction outside the camera. Lenses havethe important advantage of collecting more light than the pinhole admits

Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, Refraction*Lecture 16Optics: Reflection, RefractionOptics: Reflection, Refraction05/25/2006Lecture 16*Lecture 16