1. Reflection and Refraction of Waves

2. Important Vocabulary Incident wave – original wave hitting a surface
Angle of incidence – angle of the incident wave
Reflected wave – wave that bounces off a surface
Angle of reflection – angle at which the wave is reflected
Refracted wave – wave that travels through a medium and is bent by that medium
Angle of refraction – angle at which the wave is refracted

3. More Important Vocabulary
Converge – waves/rays come together and meet at a certain point
Diverge – waves/rays disperse and move away from a certain point
Convex – curved outward
Concave – curved inward

4. θi = θr Law of Reflection
When a ray of light is reflected, the angle of incidence is equal to the angle of reflection
θi = θr

5. Reflection continued…
When an object is reflected, an image is created in the mirror
The image in the mirror is the same distance at which it is reflected

6. Virtual vs. Real Images
Real Image – waves converge when they hit the mirror
Ex: convex and concave mirrors

7. Virtual vs. Real Images
Virtual Image – waves diverge when they hit the mirror
Ex: plane mirror

8. Law of Refraction
Refraction is the bending of waves as it moves from one medium to another medium with a different density
The more dense the medium is, the slower the wave travels
The speed of light in a vacuum is 3 x 108 m/s, so we assume that the speed of light in air is the same because the numbers are so close
c = 3 x 108 m/s
c represents the constant of the speed of light

9. Law of Refraction n = c/v n = index of refraction c = 3 x 108 m/s
The index of refraction is the ratio of the speed of light in a vacuum to the speed of light in the medium
n = c/v n = index of refraction
c = 3 x 108 m/s
v = speed of light in the medium

10. Law of Refraction
Light bends TOWARD the normal when the optical density is MORE dense
Light bends AWAY from the normal when the optical density is LESS dense
n1 = 1
n2 = 1.5
n1 = 1.5
n2 = 1

11. Law of Refraction
According to the picture and the previous slide, how would you know that water is more dense than air?

12. Law of Refraction (n1)(sin θ1) = (n2)(sin θ2)
Snell’s Law – shows mathematical relationship between the angle of incidence and angle of refraction when traveling through different media
(n1)(sin θ1) = (n2)(sin θ2)
n1 = index of refraction in medium 1
θ1 = angle of incidence
n2 = index of refraction in medium 2
θ2 = angle of refraction