The rest of physics

Question 1

what is the critical angle?

Answer 1

The angle of incidence at which the refracted ray lies on the boundary of the two substances (making the angle of refraction 90 degrees) - the largest angle of incidence for which refraction can still occur

Question 2

how would you find the critical angle?

Answer 2

use snells law (nisinΘi=nrsinΘr). Let Θi (the angle of incidence) equal the critical angle and let Θr equal 90 degrees. solve for Θcrit.

Question 3

when does total internal reflection happen? What it is? (2)

Answer 3

when the angle of incidence is greater than the critical angle, light rays reflect back into the first substance following Θi=Θr (draw a picture of this, or check L7 if needed)

Question 4

Two reasons why diamonds sparkle

Answer 4

1. high index of refraction: lots of refraction
2. low critical angle: most of the light undergoes total interal reflection

Question 5

TIR for triangular prisms: societal applications (2)

Answer 5

periscopes, binoculars

Question 6

TIR for retroreflectors: societal applications (2)

Answer 6

retroreflectors bounce light back exactly the way it came. The light-up signs that relect car headlights back, Laser-Ranging Retroreflector left on the moon

Question 7

formula given is n=c/v. Explain each variable

Answer 7

n: index of refraction
c: speed of light in vacuum
v: speed of light in medium