1. Chapter 14
Light and Reflection

2. Light is a form of electromagnetic radiation

3. All electromagnetic radiation travels at c = 3.00 x 108 m/s
c = f l
constant

5. Radio Waves
longest wavelength l ˃ 0.3 m
smallest frequency f ˂ 109 Hz
Used to transmit radio and tv signals

6. Microwaves wavelength 0.3m ˃ l ˃ 1 x 10-3m
frequency x 109 Hz ˂ f ˂ 3 x 1011 Hz
Used in radar, ovens and communication (cell phones)

7. Infrared wavelength 1 x 10-3 m ˃ l ˃ 700 nm
frequency x 1011 Hz ˂ f ˂ 4.3 x 1014 Hz
~heat~

8. Visible Light
wavelength nm (red) ˃ l ˃ 400 nm (violet) frequency x 1014 Hz ˂ f ˂ 7.5 x 1014 Hz

9. Ultraviolet (UV) light
wavelength nm ˃ l ˃ 60 nm
frequency x 1014 Hz ˂ f ˂ 5 x 1015 Hz
Causes tanning and skin cancer

10. X rays
wavelength nm ˃ l ˃ 10-4 nm frequency x 1015 Hz ˂ f ˂ 3 x 1021 Hz

11. Gamma rays Used to treat cancer
shortest wavelength nm ˃ l ˃ 10-5 nm
highest frequency x 1018 Hz ˂ f ˂ 3 x 1022 Hz
Used to treat cancer

12. Light is an “inverse square” function, brightness decreases by the square of the distance.
Double the distance will be 1/4th as bright

13. Reflection
Light can have diffuse or specular (regular) reflection

14. The angle of incidence = the angle of reflection

15. Image distance = Object distance

16. Images can be real or virtual
Real images can be projected

17. Concave Mirrors
C, center of curvature
F, focal point
Principal axis

18. Mirror Equation 1/p + 1/q = 1/f object distance focal length
image distance

19. Magnification Equation
M = h’/h = -q/p
object distance
image height
image distance
object height
+ M upright virtual
-M inverted real