Spherical Mirrors Flashcards
a plane reflecting surface changes the
direction of light without altering its vergence
if the reflecting surface is curved, it changes
the direction and vergence of the reflected light are changed
the media involved influences the
percentage of light reflected
geometry of reflected light is _____ of the media
independent
a concave mirror ____ light
converges
a concave refracting surface is one that ___ light
diverges
a convex mirror ____ light
diverges
a convex refracting surface ____ light
converges
what kind of reflecting and refracting surfaces does the cornea have
- convex refracting surface (converging)
- convex reflecting surface (diverging)
anterior and posterior cornea and anterior lens are ____ mirrors
convex
posterior lens is a ____ mirror
concave
images formed by regular reflection- mirror or refracting surface- are known as _______ images
catoptric
the optics of a mirror is completely specified by a single parameter, the _____
radius of curvature, r
image formation depends only on this one parameter
radius of curvature, r
the law of reflection is ____ of the medium in which it occurs
independent
what is another one of the mirror’s imaging properties
focal length
a spherical mirror has a single focal point F, and it is located:
between the mirror and the center of curvature, C
how is the single focal point, F, do “double duty”
it it both an object point conjugate to infinity and an image point conjugate to infinity
for concave mirror, are f and r values positive or negative
positive
for convex mirror, are f and r values positive or negative
negative
an object distance is positive if measured in
the same direction as incident light
an image distance is positive if measured in the
same direction as reflected light
relationship of r and f
f = r/2
lateral magnification, m =
m= x’/x
concave mirror with a real object located to the left of the center of curvature (C), the image is
real, inverted, and reduced
concave mirror with a real object located between C and the focal point F, the image is
real, inverted, and enlarged
concave mirror with a real object between F and the mirror, the image is
virtual, upright, and enlarged
mirror with a real object at C, the image is
virtual, upright, and enlarged
concave mirror with a virtual object (right, behind mirror), the image is
real, upright, and reduced
convex mirror with a real object, image is
virtual, upright, and reduced
convex mirror with a virtual object between the mirror and F, image is
real, upright, and enlarged
convex mirror with a virtual object between F and C, the image is
virtual, inverted, and enlarged
convex mirror with a virtual object to the right of C, the image is
virtual, inverted, and reduced
real life application of case “a concave mirror with a real object outside of C, forming a real, inverted image” is
reflecting telescope, astronomical telescopes
real life application of case “a concave mirror with a real object placed between D and the mirror, forming a virtual, upright, and enlarged image” is
very common, magnifying or cosmetic mirror
real life application of case “a convex mirror with a real object forming a virtual, upright, and reduced image” is
side-view mirrors, (mirrors used to expand the field of view)
does the index affect the power of the mirror?
yes, the power of a mirror does depend on index
mirror power, P is also known as _____ power
catoptric
concave mirror with a converging power has a __ power
+ plus
convex mirror with a diverging power has a ___ power
- minus
does n matter for focal power and/or for focal length
- focal power of a mirror depends on n
- focal length of a mirror is independent of n
the lens-mirror power is defined as
the sum of two times the front surface power and the mirror power in the medium of index n’
P(n’) power of the mirror in the medium of index n’ =
n’/f or 2n’/r
D1 (the power of the front surface of the lens) =
(n’-1)/r
equation for lens-mirror power sum=
2D1 + P(n’)
focal length of equivalent mirror (lens-mirror) =
1/D(LM)
describe spherical abberations
rays falling on the periphery of a mirror (or lens) will, after reflection, cross the optical axis at positions different from rats falling on the central part of the mirror
how can you remove the problem of spherical aberrations
by making the mirror surface slightly different from spherical (so, aspherical)
-or parabolic surface
what does a keratometer measure?
the refractive power of the cornea can be estimated
what is the keratometer actually measuring?
it measures the size o the image of a distant real object formed by a convo mirror (cornea)
by what comparisons can the keratometer estimate the power of the cornea?
since the radius of curvature is proportional to the image size, the power of the cornea may be estimated, based upon the value chose for the refractive index of the cornea
