1. Chapter 15
Refraction

2. When light goes from one medium into another, it changes speed
When light goes from one medium into another, it changes speed. If light comes in at an angle, this causes it to change direction.

3. normal
light qi
Light is
faster
Air
Water
slower qr

4. normal
light qi
Light is
slower
Glass
Air
faster qr

5. wave crests l
Air l
smaller
Water
slower

6. speed of light in medium
The Index of Refraction is a measure of how much light slows down in a medium compared to its speed in a vacuum
speed of light
in a vacuum
3 x 108 m/s
index of refraction
speed of light in medium

7. Indices of Refraction
material n
diamond
flint glass
H2O ice
water
air
vacuum

8. When light goes from a lower “n” to a higher, it bends toward the normal and vice-versa.
air
glass

9. Draw where the light would go as it changed media
glass
air

10. Refraction changes the apparent positions of objects in different media.

11. Snell’s Law nisinqi = nrsinqr 43° 30.8°
What is the angle of refraction?
air n = 1
water n = 1.33
30.8°

12. Ray 1: Parallel, then through f Ray 2: Through f, then parallel
Ray Diagrams for Convex Lenses f f
Ray 1: Parallel, then through f
Ray 2: Through f, then parallel
Ray 3: Through the lens center

13. Ray Diagram for Concave Lenses