2. nwater·sin(?) = nair·sin(90)
c v
Snell's Law
n1·sin(σ1) = n2·sin(σ2)
nwater·sin(?) = nair·sin(90)
Air – “fast”
Water – “slow” ?
Critical Angle

3. Total internal reflection.
n1sin1= n2sin2
If θ2=90
sin2=1  θ1= θc
 n1sinc= n2
Critical Angle

4. ndiamond·sin(σ1) = nair·sin(σ2)
c v
Snell's Law
ndiamond·sin(σ1) = nair·sin(σ2)
·sin(?) = ·sin(90)
299,792, , 932,393
299,792, , 702,547
? = 24.4°
$15 Million 84 Carat Diamond Up For Auction!
24.4°

5. Light Box activity

7. LAB – Index of Refraction
Find the speed of light of in this.
What angle of incidence would produce the critical angle on the opposite face of the equilateral tiangle? Then test! ? θc
nacrylic = 1.5
θc = 41.8°
?= 27.9°

8. Total Internal Reflection
Web Link: Total internal reflection
Examples:
Fiber Optics
Diamonds
Total internal reflection

9. Air – “fast” Water – “slow”

11. Atlee High School, Student: Matthew Jay Rohr, Teacher: Jeremy Watts

12. http://www. lightandmatter

13. The glass fibre has a second glass cladding of a lower n (and then a plastic covering)
This allows the light to totally internally reflect down the fibre.

14. Optical fiber communication system
Electrical/optical converter
Decoder
Electric signal
Fiber
Optical/electrical converter
Encoder
Repeater
Digital encoding scheme
for optical communications
“One”
“Zero”
High-power pulse  “one”
Low-power pulse  “zero”
High-power pulse  “One”

15. Medicine
a) to view
An endoscope can be inserted into the body with minimal surgery (non-invasive).

16. Once in the body it can diagnose and/or treat a condition.