Geometrical Optics Flashcards
Reflection
the rebounding of incident light waves at the boundary of a medium
law of reflection
states that the incident angle will equal the angle of reflection, as measured form the normal
spherical mirrors
have centers and radii of curvature as well as focal points
concave mirrors
are converging systems and can produce real, inverted images or virtual, upright images, depending on the placement of the object relative to the focus
convex mirrors
are diverging systems and will only produce virtual, upright images
plane mirrors
produces virtual, upright images; these images are always the same size as the object. they may be thought of as spherical mirrors with infinite radii of curvature.
refraction
the bending of light as it passes from one medium to another. this speed change causes refraction
the amount of refraction depends on the wavelength of the light involved; this behavior causes ____ of light through prism
dispersion
Snell’s law (the law of refraction)
states that there is an inverse relationship between the index of refraction and the sine of the angle of refraction (measured from the normal)
total internal reflection
occurs when light cannot be refracted out of a medium and is instead reflected back inside the medium
happens when light moves from a medium with a higher index of refraction to a medium with a lower index of refraction with a high incident angle
critical angle
the minimum incident angle at which total internal reflection occurs
lenses
refract light to form images of objects
thin symmetrical lenses have focal points on each side.
convex lenses
are converging systems and can produce real, inverted images or virtual, upright images
concave lenses
are diverging systems and will only produce virtual, upright images
lenses with non - negligible thickness require use of the
lensmarker’s equation
images created by a mirror can either be
real or virtue
an image is said to be real if
the light actually converges at the position of the image
an image is said to be virtue if
the light only appears to be coming form the position of the image but does not actually converge there.
plane mirrors (flat reflective surfaces)
cause neither convergence nor divergence or elected light rays
plane mirrors always create
virtual images
center of curvature
a point on the optical axis located at a distance equal to the radio of curvature from the vertex of the mirror
focal length (f)
the distance between the focal point (F) and the mirror
using the image distance calculation,
if the image has positive distance (i>0), it is
a REAL image which implies that the imagine is in FRONT of the mirror
using the image distance calculation,
if the image has negative distance (i
VIRTUAL and thus located behind the mirror
a negative magnification signifies:
an INVERTED image
a positive magnification signifies:
an UPRIGHT image
ray diagram
useful for getting an approximation of where an image is
on MCAT, this diagram is helpful for a quick determination of the type of image that will be produced by an object some distnaacen from the mirror (real vs virtual, inverted bs upright, and magnified vs reduced).
ray parallel to axis =
reflects back through focal point
ray through focal point =
reflects back parallel to axis
ray to center of mirror =
reflects back at some angle relative to normal
Chromatic aberration
a dispersive effect within spherical lens
Dispersion
when wavelengths of light separate from each other
the component color in the dispersion prism that experienced the least amount of refraction:
red; therefore found at the top
the component color in the dispersion prism that experienced the most amount of refraction:
violet; therefore found at the bottom
NOTE:
as light enters the medium with a different index of refraction, the wavelength changes but the frequency of the light does not.
spherical aberration
a blurring of the periphery of an image as a result of inadequate reflection of parallel beams at the edge of a mirror or inadequate refraction of parallel beams at the edge of the lens
people who are near sighted need what type of lens?
diverging lens
people who are far sighted need what type of lens?
converging lens
myopia
nearsightedness
hyperopia
farsightedness
