What Is an Optical System?

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Abraham Sims
6 years ago
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1 What Is an Optical System? Anything that involves light Used to study how light behaves Optical devices: lens, mirror, prism 2 Functions: collect light rays and bend the rays to form an image

2 Rays bounce off a surface Bending of a ray when cross a different boundary

3 Incident Ray NORMAL Reflected Ray Reflection Law of reflection: ray will bounce at the same angle at which it arrives MIRROR

4 Law of Reflection

$Refraction A converging lens changes the$

5 Refraction A converging lens changes the direction of light through the process of:

6 In the picture below, the person sees the fish image in a different location than the actual fish because: Air Water The light rays reflected from the fish bend at the surface of the water.

7 The index of refraction best describes: the ability of a material to bend light rays. Material n Vacuum 1.00 Air Water 1.33 Plastic 1.49 Glass 1.56 Light slows down because the wave has to be constantly absorbed and reemitted by the atoms of the materials Diamond 2.41

8 Works by collecting the rays from an object and bending them so they form an image on film CAMERA Object: any real physical thing that gives off light Image: pictures of objects that form where light rays from the object meet

9 Time to Experiment Use a Simple Model- Laser and Prism Build Upon What You Have Learned This Magic Angle is Critical to what is going on

10 Laser/Prism Experiment - beam will travel through the air & enter the prism (AB) - direction of the beam inside the prism changes (BC) - change of direction also occurs as beam exits prism and enters the air (CD) - This is the phenomenon of refraction.

11 The human focuses on objects that are near & far away because: the lens changes shape

12 Point where rays cross after passing through the converging lens

13 Convex / Concave Convex or converging. Concave or diverging

14 Lens bends the parallel light outward away from the focal point. Lens bend the parallel light rays inward toward the focal point.

15 Real Images occur when objects are placed outside the focal length of a converging lens or converging mirror Ray tracing

16 Virtual Images are formed by diverging lenses or by placing an object inside the focal length of a converging lens

17 A light ray strikes a lens parallel to the axis of the lens. Which of the following rays best represents the path of the light ray as it leaves the lens? Ray a

18 OBSERVATIONS I can see the X at first When I move my head up and down the X vanishes When the X vanishes the O takes its place This seems to be happening at the same angle, the magic angle

19 Prismatic Name Enlightenment 1. Repeat the process for the X and O but instead of the X write your first name. 2. Also write your first name in place of the O but this time underline your name. 3. What information do you now see that can help us explain what is going on?

20 OBSERVATIONS I can see my name upside-down When I move my head up and down my name vanishes When my upside-down name vanishes the underlined name takes its place, and it isn t upside-down any more This seems to be happening at the same angle, the magic angle

21 OBSERVATIONS The exiting beam exits at a different angle for each trial When I move the laser up the paper, the exiting beam angles more in the downward direction At a certain point the exiting beam disappears This seems to be happening at the same angle, the magic angle

$Conclusions from Experiment At a certain angle the beam is refracted and doesn t exit the prism This happens at$

22 Conclusions from Experiment At a certain angle the beam is refracted and doesn t exit the prism This happens at the CRITICAL ANGLE If the angle is bigger than the CRITICAL ANGLE the beam experiences TOTAL INTERNAL REFLECTION

23 Fiber Optics Optics in Everyday Life Laser Scanners Surgical Lasers Information Storage-CDs, DVDs High precision Distance Measuring Internet Telephone

24 Fiber Optics Bundles of fiber optics can send messages without lenses. Speeds the exchange of info between phone and computers (each letter different light code) Light travels 300 million m/s / Sound travels 340 m/s

25 Each color carries a signal 64 signals in one glass strand Prisms break message apart to be decoded Fiber Optics

Light & Optical Systems Reflection & Refraction. Notes

$Light & Optical Systems Reflection & Refraction. Notes$ Light & Optical Systems Reflection & Refraction Notes What is light? Light is electromagnetic radiation Ultra-violet + visible + infra-red Behavior of Light Light behaves in 2 ways particles (photons)