1. January 8, 2002PSYC202-005, Term 2, Copyright Jason Harrison 20021 Light: Properties and Characteristics Electromagnetic energy you can see

2. Properties of light Carrier of information Electromagnetic wave –Light is the region of the electromagnetic spectrum that can be perceived by human vision 0.7 um

3. Properties of light Travels in straight lines

4. angle of incidence (i) = angle of reflection (r) Properties of light Reflects from surfaces

5. sin (  i ) = n sin (  r ) n is refractive index of dense material n ≈ 1.1 - 1.3 (depends on material) Properties of Light Refracts at boundaries of transparent materials

6. Characteristics of Light Frequency (f)

7. Characteristics of Light Frequency (f)

8. Characteristics of Light Wavelength = c/f

9. Frequency corresponds to colour - high frequency (short ) = blue (380 nm) - low frequency (long ) = red (720 nm) Many frequencies aren’t seen by humans - higher frequencies -> ultraviolet (UV) - lower frequencies -> infrared (IR)

10. January 8, 2002PSYC202-005, Term 2, Copyright Jason Harrison 200210 Frequency corresponds to colour

11. January 8, 2002PSYC202-005, Term 2, Copyright Jason Harrison 200211 Electromagnetic Spectrum

12. January 8, 2002PSYC202-005, Term 2, Copyright Jason Harrison 200212 Absorption of light by atmosphere From www.tvhandbook.com/graphics/pdf_files/chapter1_1.pdf

13. January 8, 2002PSYC202-005, Term 2, Copyright Jason Harrison 200213 Absorption of light by water Electric Current From http://www.karger.ch/gazette/64/fernald/

14. Characteristics of Light Amplitude (A)

15. Characteristics of Light Amplitude (A)

16. Amplitude determines intensity (Amplitude) 2 = Energy/second = intensity – high amplitude = bright light – low amplitude = dim light

17. Finally What was the purpose of this presentation? Which question remains unanswered?

18. January 8, 2002PSYC202-005, Term 2, Copyright Jason Harrison 200218 For Thursday’s tutorial… Reading for tutorial: –Ramachandran and Blakeslee, chapter 1 Assignment due in tutorial: –www.cs.ubc.ca/~harrison/P202www.cs.ubc.ca/~harrison/P202 For Next week… Reading for lecture: Gregory, Ch 4-5 Reading for tutorial: Rama, Ch 2