Exam 1 Flashcards
Visible Light
400-700 nm
Light is a____
Wave
A____ is a series of concentric circles that travel _____ ____ the source that created it.
Wavefront, away from
Rays are drawn ___ rom the wavefront
Perpendicular
Rays indicate which direction the wavefront is traveling
Steeper vergence (curvature of a wavefront) =
More curved, smaller circle, closer to the source, more energy
Flatter vergence (curvature of a wavefront)=
less curved, larger circles, traveling away from the source, less energy
Light rays traveling away from a source
Divergence
Light rays headed toward a focal point
Convergence
Light rays at an infinite distance will be
parallel
Refraction
measurement of the focusing characteristics of an eye or eyes
The radius of the _____ determines the dioptric power
Curvature, more curve =higher diopter
Thick middle, lighter edges ____ light
Convex, converge
Thin middle, thick edge ____ light
Concave, diverge
When we look at something we are looking at the _____ of that something
Image
Focal point right on the retina
Emmetropic
Light rays focus in front of the retina
Myopic
Light rays focus behind the retina
Hyperopic
Plus lenses are ____ and make light more _____
Convex, convergent
Minus lenses are _____ and make light more _____
Concave, divergent
Any color, interesting patterns, produced in sheets, can be molded, lightweight
Zylonite - Zyl: Cellulose Acetate
Disadvantages of Zyl
No shape memory, warping in heat, not super durable, decrease strength, can whiten by skin oils
Thermoplastic and silky, polyamide or glidamide, unbreakable and lightweight, stiff but flexible, hard to adjust, resistant to temp extremes
Nylon
Hypoallergenic, shape memory, more difficult to adjust, brittle when cold, very light, no shrinkage, molded,
Optyl
Nylon based plastic, hypoallergenic, lighter than zyl, more transparent colors
Cellulose Acetate Propionate
Monel, most common for metal, plated with palladium, coating can rub off
Nickel-Steel