Chapter 22 Flashcards
(8 cards)
How does refraction and reflection work?
When light traveling in one medium encounters a boundary leading into a second medium, some of the light is transmitted and some is reflected
Far away from a source, rays are parallel and the wave fronts are planes
Slide 1 feb 12
What are specular reflections and diffuse reflections?
Specular- reflections from a smooth surface, incident beams are parallel and reflected beams are parallel
Diffuse- reflection off rough surface
Rough means holes and pits in the surface are large compared to the wavelength of light
Slide 3-5 Feb 12
Where are angles of light always measured?
Relative to the normal (perpendicular to the reflecting surface)
Angle on equals angle off
Slide 7 Feb 12
How is a lights speed affects by change in wavelength?
Frequency remains constant
So increase in light speed means longer wavelength
Decrease in light speed equals shorter wavelength
Slide 10-11 Feb 12
If a light beam with longer wavelength enters a medium that shortens the wavelength, which way does the new beam bend?
How is the index of refraction changed (n)?
Toward the normal
The new index of refraction is greater than the old one
Slide 15 Feb 12
Slide 20 Feb 12
Slide 25 Feb 12
What is dispersion?
The dependence of index of refraction on wavelength is dispersion
Slide 31-34 Feb 12
What is Huygens principle?
Assumed light is a form of wave motion
All points on a wave front are taken as point sources for the production of spherical secondary waves (wavelets) that propagate in the forward direction with speeds characteristic of waves in that medium
Slide 2 Feb 14
What is total internal refraction?
When light reaches a boundary where the index of refraction decreases, there’s a critical angle above which no light is transmitted
At the critical angel, the angle of refraction is 90 degrees which means that the light moves along the surface between the two media
Slide 5-6 Feb 14
