Chapter 18 Flashcards
what is a wave front?
a surface passing through points of a wave that have the same phase and amplitude
what is ray approximation?
is used to represent beams of light
what is an incident ray?
travels in a medium, some light is reflected back
what is a refracted ray?
the refracted ray enters the second medium and is bent at the boundary
the incident ray is equal to the…?
the incident ray is always equal to the reflected ray
what is specular reflection?
is reflection from a smooth (highly polished) surface
what is diffuse reflection?
is reflection from a rough surface, the reflected rays travel in a variety of directions
what is snell’s law?
The angle of refraction depends on the indices of the two media
n1sinθ1 = n2sinθ2
LHC means?
Low to High index means the refracted ray bends closer to the normal line
HLA means?
High to Low index means the refracted ray bends away from the normal line
Violet light does what?
violet light bends more towards the normal line than red
what total internal reflection?
can occur when light attempts to move from a medium with a higher index of refraction to one with a lower index of refraction (HLA)
n1sinθc = n2sin(90)
how to see objects with a flat mirror?
the reflected rays follow the law of reflection
what are the properties of flat mirrors?
s = s' h = h' m = 1 ALWAYS the image is always virtual the image has the same orientation as the object
what is a concave mirror (positive f) (rays are reflected not refracted)?
it curves inward like a cave
Principal Rays for a concave mirror:
1. ray in parallel to axis, out through f
2. ray in through f, out parallel to axis
3. ray in through c, out along itself
4. in to V, then law of reflection θi = θr
what is a convex mirror (negative f) (rays are reflected not refracted)?
it curves outward opposite of a cave
Principal Rays for a convex Mirror:
1. ray in parallel to axis, out as if from f
2. ray in towards f, out parallel to axis
3. ray in towards C, out along itself
4. ray in to V, then law of reflection θi = θr
For a concave mirror what do these stand for?
BUV = Bigger, Upright, Virtual (when image is between the mirror and the focal point) SIV = Smaller, Inverted, and Real (when image is beyond the focal point)
For a convex mirror what is the ONLY possible outcome for images?
SUV = smaller, upright, virtual
For mirrors, what does real and virtual mean?
Real : image formed in front of mirror
Virtual : Image formed behind the mirror
THIS IS OPPOSITE FOR LENSES
what are converging lenses?
Positive focal lengths, thickest in the middle
what are diverging lenses?
Negative focal lengths, thickest at the edges
what is the lens-maker’s equation?
1/f = (n-1)(1/R1 - 1/R2)
What are the Principal Rays for Thin lenses (rays refracted so they pass through the lens, they are not reflected)?
- Ray in parallel to axis, out through f
- Ray in through C, out through C
- Ray in through f, out parallel
What do you do for combinations of two lenses?
- Pretend as if the second lens was not there and find your image for the first lens
- then the image of the first lens becomes your object for your second lens
- the total magnification M is the product of the two separate lenses:
M =m1m2
