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James Clerk Maxwell (1831 – 1879)

James Clerk Maxwell (1831 – 1879). Electromagnetic (light) Waves. Radio…not just AM & FM. AM vs FM radio. Frequency Modulated. Amplitude Modulated. Both AM & FM radio signals have advantages and disadvantages.

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James Clerk Maxwell (1831 – 1879)

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  1. James ClerkMaxwell (1831 – 1879)

  2. Electromagnetic (light) Waves

  3. Radio…not just AM & FM

  4. AM vs FM radio Frequency Modulated Amplitude Modulated

  5. Both AM & FM radio signals have advantages and disadvantages. • Generally, AM waves have much longer wavelengths than FM waves and can DIFFRACT better than FM waves and can travel greater distances before the signal fades. FM is more direct line of sight. • However, because information is coded in the amplitude of an AM wave, power lines and lightning can influence the amplitude and are more likely to interfere with the AM wave. • FM has a greater range of frequency which is better for music whereas AM is better for talk radio since there isn’t much fluctuation in a person’s voice.

  6. Microwaves

  7. Infrared

  8. Thermogram We radiate infrared light aka “heat”

  9. Visible

  10. Ultraviolet

  11. X-RAYS

  12. Gamma Ray

  13. Reflection and Refraction of Light

  14. Rays instead of waves approximation A ray of light is an imaginary line drawn along the direction of travel of the light beams. We use this instead of a wave.

  15. Law of Reflection θi θr

  16. 2 types of reflection:

  17. With diffuse reflection, your eye sees reflected light at all angles. With specular reflection (from a mirror), your eye must be in the correct position.

  18. Refraction of Light When a ray of light enters a different medium at an angle other than 0o with the normal, it will bend or REFRACT due to a speed change due to material change.

  19. θi>θr θi<θr θi θi θr θr

  20. The Index of Refraction

  21. Snell’s Law of Refraction

  22. A ray of light is incident on the surface of a block of clearice (1.309) at an angle of 40.0° with the normal. Part of the lightis reflected and part is refracted. Find the angle betweenthe reflected and refracted light.

  23. Frequency Between Media

  24. The light emitted by a helium–neon laser has a wavelengthof 632.8nm in air. As the light travels from air intozircon (1.923), find a) its speed in zircon b) its frequency inzircon c) its wavelength in zircon.

  25. Illusions from refraction

  26. Sunset not really there?

  27. Mirage

  28. Dispersion

  29. Variation of Index of Refraction with Wavelength

  30. Critical Angle

  31. Total Internal Reflection

  32. TIR and ‘bling bling’

  33. Fiber Optics and TIR Plastic or glass rods are used to “pipe” light from one place to another This ‘light’ can be used to carry information at light speed Fiber Optics, Medical Endoscopes

  34. The Rainbow

  35. Observing the Rainbow If a raindrop high in the sky is observed, the red ray is seen A drop lower in the sky would direct violet light to the observer The other colors of the spectra lie in between the red and the violet

  36. A bright underwater flood light at the bottom of a 2.75-m deep pool is positioned 1.85 m from one edge of the pool. At what angle will light emerge from the surface of the water at the edge of the pool. Assume the pool is filled to the brim with water.

  37. MIRRORS

  38. Image Types for Mirrors

  39. Image characteristics: • TYPE – • B) ORIENTATION • C) MAGNIFICATION (M) • D) Position & height of image and object

  40. Reflection & Image Formation by a Plane Mirror What you see when you look into a plane (flat) mirror is an image, which appears to be behind the mirror.

  41. Properties of the Image Formed by a Plane/Flat Mirror

  42. Concave Mirror Converges light rays after reflection

  43. Parallel light rays reflecting off of concave mirror Note how all 4 rays reflect and converge at common point. This is called FOCAL POINT.

  44. Focal Length Incoming rays are parallel and all reflect through a common point called the FOCAL POINT, F.

  45. Applications of concave mirror PARABOLIC REFLECTORS - Behind flashlight bulbs, headlights, searchlights. projects light out in a concentrated beam…bulb is placed at focal pt. SATELLITE DISH - Microwaves strike dish and reflect and collect at the receiver (at focal point) SOLAR COOKER MAKEUP MIRROR…provides an enlarged image of face when held close to face

  46. Convex Mirror Diverges light rays after reflection

  47. APPLICATIONS:

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