1. A wave of electromagnetic energy moves through empty space at the speed of light.
A wave of electromagnetic energy moves through empty space at the speed of light, 299,792.5 kilometers per second. The wave carries itself along by continually changing its electric energy into magnetic energy and vice versa.

2. Photons—”packets” of energy—stream away from a light source at the speed of light.

7. "1,000,000,000,000 Frames/Second- Youtube video

8. Practice
1. Calculate the λ of a wave given the frequency of the radiation is 5.10 x 1014 Hz
2. Calculate the frequency of red light with λ = 6.50 x 10-7m.
3. What is the frequency of yellow light, λ = 556nm?

9. Warm up
The distance to the moon can be found with the help of mirrors left on the moon by astronauts. A pulse of light is sent to the moon and returns to Earth in s. Calculate the distance from Earth to the moon.

10. Color by addition
When two or more colors of light are shined together they produce a new color.

11. Color by subtraction
The ultimate color appearance of an object is determined by beginning with a single color and identifying which color light are subtracted from the original set

12. Primary Colors
R + G = Y
R + B = M
G + B = C

14. Complementary Colors of Light
Red and Cyan
Green and Magenta
Blue and Yellow
Any two colors of light which produce white are said to be complementary colors of each other.

17. Warm up
If an X-ray has a wavelength of 5 nm, what is its frequency?
The frequency of the most energetic gamma ray burst in the universe have been measured at 3.0 x 1021 Hz. What is the wavelength of this burst?

18. Diffuse reflection – ray reflect in all different directions(right)
regular reflection - reflected rays are all parallel to each other(left)

19. Law of reflection
The angle of incidence θi is equal to the angle of reflection θr. When the angle is measured from the normal line.
Normal line-line perpendicular to a boundary.

20. polarization

21. Plane mirrors
hi = height of the image ho = height of the object di = distance to the image do= distance to the object

22. Principle of Optical reflection
When a ray of light strikes a plane mirror, the light ray reflects off the mirror.
According to the law of reflection, the angle of incidence equals the angle of reflection.

23. Property of mirrors is right left reflection
A shirt that says Nike will read
ekiN

24. Images formed by plane mirror

25. Practice
Draw a diagram that shows a mirror with a normal line and a ray of light hitting the mirror at an angle of incidence of 60 degrees.
What is the angle between the incident ray and the reflected ray.
A ray of light strikes a mirror. The angle formed by the incident ray and the mirror is 25 degrees. What are the measurements of the angle of incidence and the angle of reflection?

26. Mirror Mirror on the wall

27. L P

28. Principle of Optical refraction

29. Refraction
Refraction of light  change in direction of light ray when a ray passes from one medium to another due to a difference in densities of the two media
Angle of incidence - 1
Angle of refraction - 2

30. Index of Refraction
The index of refraction (n)  ratio of the speed of light in a vacuum to the speed of light in a different medium.

31. Using index of refraction

32. Principle of Optical refraction
Snell’s Law: describes the angle of refracted light.
n1,2 = index of refraction
n1 sin θ1 = n2 sin θ2
If n1 < n2 ; then goes into a more optically dense medium and bends towards the normal line.
If n1 > n2 ; then bends away from the normal

33. Snell’s Law practice
1. Light traveling in air (n1 =1) strikes a flat piece of uniformly thick glass at an incident angle of 60.0. If the index of refraction of the glass is a) what is the angle of refraction θ in the glass b) what is the angle θ at which the ray emerges from the glass?

34. More practice
2. A beam of light that has a wavelength of 651 nm traveling in air (n=1) is incident on a slab of transparent material. The angle of incidence is 35.0. The angle of refraction is 23.4. Find index of refraction for the slab.

35. Warm up
Sketch a ray going from crown glass into air.
This ray of light is incident in crown glass (n =1.54) at an angle of 31 . What is the angle of refraction?

36. Research
Diffraction –
Interference-
Include a picture of both
Young’s 2x movie

37. Warm up
1.A light beam coming from an underwater spotlight exits the water (n=1.33) at a 47.5 degree angle to the normal. At what angle of incident does the ray hit the air-water interface from below the surface. 2.Light passes from a medium (n=1.5) to another medium (n=1.33). Does the light ray bend towards the normal or away? 3.What color bends the most as it passes through a prism.

38. Concave/convex mirrors
How does your image change when you move from far away to close up on a concave mirror? convex mirror?

39. The inverse-square law.
The area over which light a distance d from the source is spread is 4pd2.
Light spreads out from a point source in all directions.
Light spreads out from a point source in all directions.

40. Light intensity and distance
The intensity of light decreases inversely with the square of the distance.

41. The eye

42. Atmospheric refraction makes the Sun or a star look higher in the sky than it really is.
A) Atmospheric refraction makes the Sun or a star look higher in the sky than it really is. (B) Refraction is stronger for objects nearer the horizon. (C) The Sun is flattened because refraction “lifts” its lower edge more than its upper edge. (Photo courtesy Patrick Watson.)

43. Image Formation by Lenses

44. Image Formation by Lenses

53. The object is located beyond 2F

54. The object is located at 2F

55. The object is located between 2F and F

56. The object is located at F

57. Virtual images
Virtual images are images that are formed in locations where light does not actually reach
Virtual images are created by diverging rays of light

58. Properties of images formed by plane mirrors
Images formed by plane mirrors are upright, virtual and the same size as the object
The distance to the object is the same as the distance to the image do = di
Height of object equals height of image ho = hi

59. Concave Mirrors
Spherical mirrors can be thought of as a portion of a sphere which was sliced away and then silvered on one of the sides to form a reflecting surface.
Concave mirrors were silvered on the inside of the sphere and
convex mirrors were silvered on the outside of the sphere.

60. Concave Mirrors

61. Concave Mirrors

62. Concave Mirrors

63. Object Located At the Center of Curvature

64. Object Located Between the Center of Curvature and the Focal Point

66. Object Located Between the Focal Point and the Mirror

67. How Do We Know Light Behaves as a Wave?
When light encounters an obstacle in its path, the obstacle blocks the light and tends to cause the formation of a shadow in the region behind the obstacle. Light does not exhibit a very noticeable ability to bend around the obstacle and fill in the region behind it with light. Nonetheless, light does diffract around obstacles.