15-1: Refraction
Refraction the bending of light as it moves
from one medium to another; caused by the change in velocity of light in
different media
Snells Law light changes direction as it
moves from one medium to another (unless it travels along the normal)
Index of refraction = (speed of light in a vacuum)/(speed
of light in the medium)
When moving to a medium with a higher index of refraction,
the light bends towards the normal.
When moving to a medium with a lower index of refraction,
it bends away from the normal.
15-2: Thin lenses
Converging lenses produce real, inverted images
when the object is outside the focal point; produce virtual, upright images
when the object is inside the focal point
Diverging lenses produce upright, virtual
images
Image location can be determined by 1) a ray diagram
or 2) the thin-lens equation.
1/p + 1/q = 1/f
Magnification = h/h = q/p
Hyperopia farsightedness; close objects are
blurry; the images is focused behind the retina
Myopia nearsightedness; far objects are blurry;
the image is focused in front of the retina
Optical instruments (i.e. telescopes, microscopes)
use multiple lenses.
15-3: Optical phenomena
Total internal reflection can occur when light
moves from a material with a higher index of refraction to a material with
a lower index of refraction. If the angle of incidence is greater
than the critical angle, the ray is totally reflected at the boundary.
Fiber optics are used to carry light over long distances.
Mirages are caused by refraction of light in the Earths
atmosphere.
Dispersion light is separated into its different
wavelengths (i.e. prisms, rainbows)
Chromatic aberration is the blurriness caused
by the focusing of different colors of light at different distances |
