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51 Cards in this Set
- Front
- Back
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Optics
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Science dealing with the propagation and behaviour of light. |
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Geometric Optics
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Area of optics that deals with manipulating light with lenses and mirrors. The use of light rays to determine the path of light when it strikes as object. |
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Light
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Important form of energy. Life on Earth wouldn't survive without it.
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Electromagnetic Spectrum
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Made of several types of radiation. Two types are: 1. Visible light 2. Radio waves |
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Electromagnetic Radiation |
Made of photons.
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Radiation Waves
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Each wave in the electromagnetic spectrum consists of photons with different amounts of energy. |
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Wavelengths (meters)
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Radio (10^3) Microwave (10^-2) Infrared (10^-5) Visible (.5 * 10^-6) Ultraviolet (10^-8) X-ray (10^-10) Gamma Ray (10^-12) |
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Risks
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Waves with higher energy can penetrate human tissues and cause: a) damage to cells b) mutations c) cancer |
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White Light |
White light sources such as the Sun and incandescent light bulbs give off the full spectrum of colours.
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Visible Spectrum
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Part of the electromagnetic spectrum that can be seen by humans. Made of the colours: red, orange, yellow, green, blue, indigo, and violet |
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Visible White Light
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Made of several colours, each having a different wave length and frequency.
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Waves
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Can be compared to waves of water. Will vary in the distance to the next wave. Ex: X-rays are very close to each other, therefore have a short wave length. |
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How light travels
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In a straight line as long as it is moving though the same medium. It can be made to change direction using reflection and refraction. |
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Medium
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The substance through which light is traveling.
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Ray Model of Light |
Light is represented as straight lines called rays, which show the direction that light travels.
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Ray
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The path followed by the light that is represented by a direct straight line.
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Beam
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A bundle of rays.
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Parallel Beam
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A beam in which the rays are parallel to each other.
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Converging Beam
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A beam in which the rays move closer together and meet.
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Diverging Beam
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A beam in which the rays spread out.
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Ray Diagrams
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Drawings that show the path that the light takes after it leaves its source. Can help explain why the brightness changes with distance; the more rays that reach your eyes, the brighter the light appears. |
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Types of Media
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Substances may be classifies according to how they transmit, reflect and absorb light.
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Transparent
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Transmits all or almost all of the incident light so that objects can be seen clearly through them. Ex: Window glass, water, air |
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Translucent
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Transmits light, but some light is scattered (absorbed and reflected) so the object can not be seen clearly. Ex: Frosted glass, clouds, waxed paper |
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Opaque
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Does not transmit any incident light. It is all absorbed (causing the material to heat up) or reflected. Objects behind the material cannot be seen. Ex: Metal, rocks, wood |
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Shadows
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A dark region that forms behind an object that is being illuminated more brightly on one side than the other.
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How are shadows formed?
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When some or all of the light falling on the object is absorbed or reflected. The result when an opaque object blocks the direct light source. |
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What does the size of a shadow depend on?
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1) The size of the object blocking the source of light. 2) The distance of the blocking object from the light source. |
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Umbra
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The innermost and darkest part of a shadow.
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Penumbra
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The region in which only a portion of the light source is obscured.
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Incandescent |
Produces light as a result of high temperature.
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Electric Discharge
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Produces light by passing an electric current through a gas. |
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Phosphorescence |
Produces light by absorbing ultraviolet
light, resulting in the emission of a visible light over an extended period of time. |
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Fluorescence
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Immediate emission of visible light as a result of the absorption of ultraviolet light.
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Chemiluminescence
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Direct production of light as the result of a chemical reaction. Little or no heat is produced.
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Bioluminescence
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Light production in living organisms. Results from a chemical reaction with little or no heat being produced.
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Triboluminescence
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Production of light from friction.
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LED
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Light being produced as an electric current flows in a semiconductor.
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Incident Light
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Light coming directly from a luminous object.
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Reflection
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Bouncing of incident light off a medium (translucent or opaque).
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Refraction
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Bending of light rays as it travels from one medium to another.
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Incident Ray
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Original incoming ray. |
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Reflected Ray
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Ray that bounces off a mirror.
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Normal
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A line that is perpendicular (right angle to) the reflecting surface.
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Angle of Incident
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Angle between the incident ray and the normal.
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Angle of Reflection
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Angle between the reflected ray and the normal.
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Plane
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Flat
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Vertex
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Where lines meet on mirror.
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Laws of Reflection
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1) The angle of incident equals the angle or reflection. 2) The incident ray, normal, and reflected ray all lie on the same plane. |
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Regular (Specular) Reflection
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When the incident rays that are parallel are reflected so they remain parallel. Ex: Calm water, mirror (flat), shiny metal |
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Diffuse Reflection
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When incident rays that are parallel are reflected at different angles. Ex: Rough water, crumbled aluminum foil |
