# Shared Flashcard Set

## Details

Science Exam Review- Optics
58
Science
01/26/2010

Term
 Describe a converging lens
Definition
 thicker in the middle, tapered on the ends. ()
Term
 Describe a diverging lens
Definition
 thicker on the ends, tapered in the middle. )(
Term
 angle of incidence
Definition
 angle between incident ray and normal
Term
 angle of refraction
Definition
 angle between refracted ray and normal
Term
 normal
Definition
 perpendicular to plane
Term
 images in mirrors are ______ inverted
Definition
 laterally
Term
 PA: Principal Axis
Definition
 The line through the centre of curvature to the midpoint of the mirror
Term
 V: Vertex
Definition
 The point where the principal axis meets the mirror
Term
 C: Centre of Curvature-
Definition
 the centre of the “sphere” whose surface has been used to make the mirror
Term
 F: Focus:
Definition
 the point at which the light rays parallel to the principal axis converge when they are reflected off the mirror (Located behind the mirror for diverging mirrors
Term
 f: Focal length-
Definition
 the distance between the vertex and the focus
Term
 For a concave(converging) mirror, light rays parallel to the principal axis converge here
Definition
 focus point
Term
 In a convex(diverging mirror), what is the focus point?
Definition
 Where the reflected rays appear to originate from; the brain traces them back to this point.
Term
 SALT stands for:
Definition
 Size (Smaller, larger), Attitude (Upright or inverted), Location, Type (Real or virtual)
Term
 focal length is negative if mirror is:
Definition
 diverging
Term
 distance of image is negative if:
Definition
 image is virtual
Term
 height of image is _______ if measured down from:
Definition
 negative, principal axis
Term
 light travels fastest in a ___________
Definition
 vacuum
Term
 what is the speed of light in a vacuum?
Definition
 3.00 x 10^8
Term
 Light bends because:
Definition
 it travels at different speeds in different mediums
Term
 A ray going from a faster medium to a slower medium will bend towards/away from the normal.
Definition
 A ray going from a faster medium to a slower medium will bend towards the normal.
Term
 Light travelling from a slower medium to a faster one will:
Definition
 bend away from the normal
Term
 Rays that enter mediums at curved boundaries refract:
Definition
 the same way they do when the boundary is straight
Term
 True/false: sometimes both reflection and refraction occur
Definition
 true
Term
 What is the critical angle of a medium?
Definition
 the angle before total internal reflection will occur.
Term
 How do you find the critical angle?
Definition
 Use Snell's law (n1sinθ1=n2sinθ2), and setθr to 90 degrees
Term
 Describe total internal reflection.
Definition
 When the angle of refraction is ninety degrees and light travels along the boundary of a medium, unable to escape until the end.
Term
 Give an example of when total internal reflection is used.
Definition
 fiber optic cables etc.
Term
 With converging lenses, the focus is a) on the same side as the objectb) on the different side of the object
Definition
 b)on the different side of the object.
Term
 Diverging lenses have the focus on thea)same side of the objectb)different side of the object
Definition
 1)on the same side of the object
Term
 What is the cornea and what does it do?
Definition
 The outer surface of your eye, where light enters. Even though it's made of living cells, it's completely clear.
Term
 What is the hole that allows light to pass into the eye?
Definition
 The pupil
Term
 What does the iris do?
Definition
 The iris controls the amount of light entering the eye. In bright light,it contracts,and it dilates in dim light.
Term
 This inner lining at the back of your eye acts as a form of projection screen for light entering your eye.
Definition
 retina
Term
 Describe the lens of your eye.
Definition
 A convex lens that lets you focus on an object no matter where it is. Controlled by a circle of muscles that, when contracted, shrink the lens to see up close, and relax to expand the lens to see distant objects.
Term
 What are photoreceptors?
Definition
 Cells in the retina that are receptive to light; rods and cones. Rods detect shape, while cones detect color (red, green, and blue)
Term
 How does the eye work? Describe the process.
Definition
 Light passes through the cornea, and then through the retina to the lens, where photoreceptors change the light into impulses that are sent along the optic nerve to the brain.
Term
 What is the medical name for far-sightedness? Describe the condition and what type of lens you would need to fix it.
Definition
 Hyperopia. When the distance between the retina and the lens is too short, or the corneal lens is too weak. The problem is fixed with a converging lens.
Term
 Farsightedness can also be related to age, in which case it is called ______.How is this caused?
Definition
 Presbyopia; when the lens becomes too rigid to flex and thus you can't focus well.
Term
 What is myopia, what causes it, and what lens is needed to fix it?
Definition
 Myopia is near-sightedness (meaning you can see near). This is when the distance between the lens and the retina is too large, or when the corneal lens is too strong. Fixed with a diverging lens.
Term
 What is astigmatism, how does it affect those who have it, and what type of lens is needed to fix it?
Definition
 An irregularly shaped eye; one can see only along either horizontal/vertical lines, and not the other way. Fixed with a cylindrical lens.
Term
 Can electromagnetic fields travel through empty space?
Definition
 Yes
Term
 What are electromagnetic waves?
Definition
 Wave pattern of electric and magnetic fields. (Never would have guessed.)
Term
 Low energy electromagnetic waves have: ____ frequency and ____ waves.
Definition
 Low energy waves have low frequency and long waves.
Term
 High energy electromagnetic waves have ______ frequency and ______ waves.
Definition
 High frequency and small waves.
Term
 Name the type of light in order of frequency, lowest to highest.
Definition
 o Radio Waveso Microwaveso Infraredo Visible light (All the colours ROYGBIV)o Ultravioleto X-rayso Gamma rays
Term
 What is dispersion?
Definition
 White light is made up of all the different types of visible light; when white light is passed through a prism, the different wavelengths bend different amounts, dispersing and showing us a visible spectrum.
Term
 What is bioluminescence? Give an example of where it is found.
Definition
 The production and emission of light from a living creature; e.g. a firefly
Term
 Light produced by an object at a high temperature is called:
Definition
 incandescent light
Term
 True or false: incandescent light is extremely inefficient?
Definition
 True
Term
 Describe fluorescent light.
Definition
 Light emitted by a substance when exposed to electromagnetic radiation.
Term
 How do fluorescent light bulbs work?
Definition
 When electricity passes through bulbs, atoms in the gas are energized, releasing UV radiation, which strikes the phosphor and makes it glow and release light.
Term
 ________ is the ability to store energy from a light source and then emit it over a longer period of time. For example, glow in the dark objects
Definition
 Phosphorescence.
Term
 Producing light from friction (like smashing hard candies) is called:
Definition
 Triboluminescence
Term
 What is electric discharge?
Definition
 When electricity is passed through the air or another gas and produces light (like neon).
Term
 ________ is the process of turning electricity directly into light (like in LEDs)
Definition
 Electro-luminescence.
Term
 Equation with the focus, distance of object, and the distance of image. Can be used to find either.
Definition
 1/f = 1/do+ 1/di
Term
 The formula for magnification.
Definition
 m=hi/ho - di/do
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