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114 Cards in this Set
- Front
- Back
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Wave Theory
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Theory that states that light is a wave propagating in ether
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Christian Huygens
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Formulated the Wave theory in the year 1690
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Corpuscular Theory
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According to this theory, light consists of tiny particles emitted by a luminous object
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Isaac Newton
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Who formulated the corpuscular theory?
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Particle theory of light
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Other name for Corpuscular Theory
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Electromagnetic Theory
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"Light is an electronagnetic wave."
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James Clerk Maxwell
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Formulated the electromagnetic theory
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Quantum Theory
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Light is emitted in discrete packets of energy. Light is said to have dual nature: particle and wave.
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Max Planck
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Formulated the Quantum Theory
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Quanta
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discrete packets of energy
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Einstein
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Called each quantum of energy as PHOTON
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Light
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part of electromagnetic spectrum visible to the unaided eye with a wavelength of 400nm-700nm
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Optics
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study of light and its properties
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Geometric Optics
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uses the ray model of light
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Ray optics
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other name for geometric optics
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Physical Optics
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uses the wave model of light
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Wave optics
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other name for physical optics
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Rectilinear Propagation of Light / Fermat's principle of least time
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Principle that states that the path taken by light in going from one point to another is the path that requires the least time.
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Pierre de Fermat
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formulated the principle that determines the path of light
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Lunar Eclipse
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The earth blocks the sunlight reflected by the moon
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Solar Eclipse
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the moon blocks the light coming from the sun
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Umbra and Penumbra
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2 regions of a shadow
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Umbra
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Part of the shadow where all of the light from the source is totally blocked.
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Penumbra
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region around the umbra where light from the source is partially blocked
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Luminous Object
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Object that can generate its own light
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Illuminated object
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Object that is not capable of producing its own light but receives light from a luminous object and reflects this light to our eyes
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Luminous intensity
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defines the strength or brightness of a source of light
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Candela (cd)
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SI unit for luminous intensity
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Illumination
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Amount of light falling on a unit area of a surface. Represented by the letter "E".
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E = I/d^2
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Formula for illumination
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Lux
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SI Unit for illumination
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Reflected Transmitted Refracted Scattered Absorbed |
what happens to light when it is incident on a surface (5)
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Reflection
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turning back of light into the same medium after striking a surface
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Incident ray
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Ray that hits the surface
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Reflected Ray
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ray that rebounds from the surface
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Normal
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line perpendicular to the surface at the point of incidence
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Angle of incidence
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Angle between the incident and normal
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Law of Reflection
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said to be formulated by Euclid
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The incident ray, the reflected ray and the normal to the surface are on the same plane.
The angle of incidence equal to the angle of reflection |
the law of reflection states that... (2)
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Regular/Specular reflection
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Reflection from a smooth surface. Reflected rays are parallel to each other. Creates glare
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regular/specular reflection
diffuse reflection |
2 types of reflections
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diffuse reflection
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Reflection from a rough surface. Rays are not parallel and light is scattered but each ray obeys the law of reflection
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plane and spherical mirror
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two types of mirror
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water
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man's first mirror
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Properties of a real image (Mirrors)
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Formed in front of the mirror
Can be projected on a screen Always inverted |
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Properties of a Virtual Image (Mirror)
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Apparent location of image is found by extending the reflected rays until they intersect.
Formed at the back of a mirror Cannot be focused on a screen Always upright |
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Virtual, upright, same size and same distance as the object, laterally reversed
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Images formed by plane mirrors are... (5)
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Center of curvature
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center of the sphere where the mirror was taken
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Vertex
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center of the mirror
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Radius of curvature
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Radius of the sphere. Distance between C & V
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Principal Axis
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straight line joining c & v
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Optical axis
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other name for principal axis
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Aperture
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width of the mirror
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Principal focus
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point where reflected rays meet
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Focal length
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distance from the pole to the principal focus
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f = 1/2R
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formula for focal length
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Diverging mirrors
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other name for convex mirrors
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Virual, upright, smaller
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images formed by convex mirrors
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converging mirror
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other name for concave mirrors
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Paraxial Rays
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rays that lie close to the principal axis
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The image position is at focus
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if the object is at infinity, where would the image be?
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real, inverted, very diminished
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what image is formed if the object is positioned at infinity?
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The object is between c and f
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if the image is positioned beyond c, the object is positioned where?
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Refraction
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change in the velocity of light when it passes from one medium to another of different optical density
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dense medium
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light travels slowly in an optically...
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index of refraction (n)
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ratio of speed of light in vacuum to the speed of light in the substance
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n=c/v
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formula for the index of refraction
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1. 1.0003
2. 1.33 3. 1.523 4. 2.419 |
Index of Refraction for:
1. Air 2. Water 3. Glass 4. Diamond |
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3 x 10^-8
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speed of light in vacuum
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Moving away from the normal
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if the ray of light passes obliquely from an optically dense to less dense medium, it will be...
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Willebrord Snell (1621)
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Dutch Astronomer who formulated the snell's law
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1. Dense to less dense
2. Angle of incidence is greater than critical angle |
Conditions for Total internal Reflection
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Critical Angle
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Angle of incidence where the angle of refraction is equal to 90 °
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core
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Transparent material in an optical fiber that has high index of refraction
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cladding
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Object with a lesser index of refraction
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Convex Lens
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lens thicker at the middle than at the edges
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Converging lens
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other name for convex lenes
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concave lens
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lens thicker at the edges
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diverging lens
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other name for concave lenses
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1/f=1/f1+ 1/f2
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lens maker equation
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Virtual, upright, smaller
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images formed by concave lenses
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1/f = (n-1)(1/R1 + 1/R2)
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formula for thin lenses in contact
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positive
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The radius of curvature and the Focus is ________ if convex.
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cornea
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outer thin transparent membrane that protects the eye and refract most of the incident light
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pupil
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black circle in the middle of the eye and changes in size to regulate the amount of light entering the eye
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iris
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colored circle of the eye which depends on the race
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regulate the size of the pupil
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main task of the iris
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Ignatz Von Peczely
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father of iridology (study of the iris of the eye)
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sclera
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white background of the eye
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provides structure, protection and strength
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what is the function of the sclera
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crystalline lens
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clear convex structure ar the back of pupil.
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accommodation
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ability of the lens to focus objects at different distances by changing its shape
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cilliary muscles
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muscles attached to the crystalline lens and relaxes when looking at something far
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cones
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part of the retina that can distinguish color and responsible for our daytime vision
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rods
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enables us to see in the dark
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fovea
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reguon of the most distinct vision that has no rods but has about 200,000 cones
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blind spot
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point in the retina where the optic nerves exit
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optic nerve
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its main function is to carry images from the retina to the brain
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aqueous and vitreous humor
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responsible for giving the eye its newt perfect spherical shape. they also belong yo yhe refractive system of the eye (2)
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aqueous humor
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located between the cornea and lens
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vitreous humor
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humor that is found after the lens
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visual acuity
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clarity of vision or sharpness of vision
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20/200
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if 20/20 is the standard testing distance, what visual acuity is considered legally blind (US)?
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feet
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unit used for the visual acuity
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near point of the eye
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closest distance at which an object can be seen clearly by the eye
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25 cm
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near point for young adults with normal vision
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10 cm
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near point for children with normal vision
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50 cm
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near point for the aged with normal vision
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Leonardo Da Vinci (1580)
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originator of the concept of contacy lens
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far point of the eye
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farthest distance at which an object can be seen clearly
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infinity
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far point of the normal eye
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myopia
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medical term for nearsightedness
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diverging lens
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which type of lens can correct myopia
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real, inverted and smaller
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images formed by the lens of an eye
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