OV: Optics & Vision Flashcards
Transparent
Describes materials that allow light to pass through with little or no reflection allowing you to easily see through the material; for example glass (Pg. 93)
Opaque
Describes materials that do not allow light to pass through; for example, wood, metal, cardboard, etc (Pg. 92)
Reflection
Is the changing of direction of light as it hits an opaque material.
Umbra
The fully shaded region of a shadow (Pg. 93)
Penumbra
The partially shaded region of a shadow, formed by some light passing an opaque object (Pg. 93)
Specular Reflection
Reflection off smooth surfaces (Pg. 103)
Diffuse Reflection
Reflection of light off an uneven surface, which results in light scattering in many directions (Pg. 103)
Real Image
An image that appears on the same side of a concave mirror as the object; light rays pass through the object location and the image can be projected on to a screen (Pg. 108)
Virtual Image
An image that appears to be on the other side of a plane mirror; light rays do not pass through the image location (Pg. 108)
Incident Ray
Ray of light that arrives at a mirror or enters a substance (Pg. 102)
Refraction
Change in direction of light as it travels from one material to another (Pg. 112)
Concave Mirror
Reflecting surface that is curved inward like the inside of a bowl or spoon; light rays reflected from it converge or come together (Pg. 107)
Concave Lens
Piece of transparent material that is thinner in the middle than at the edges; it diverges or spreads out light rays passing through it (Pg. 121)
Convex Lens
Piece of transparent material that is thicker in the middle that at the edges; it converges, or brings together, light rays passing through it (Pg. 121)
Convex Mirror
Outwardly-curved reflecting surface that bulges out like the back of a spoon; light rays reflected from it diverge or spread out (Pg. 107)
Visible Light Spectrum
Colours of visible light which can be seen by the eye; the colours seen in a rainbow or when light is split by a prism (Pg. 139)
Electromagnetic Radiation
All forms of radiated energy: visible light, infrared radiation, ultraviolet radiation, radio waves, X-rays, etc (Pg. 150)
Wavelength
Distance between the top or peak of one wave to the peak of the next (Pg. 151)
Ray
A directed straight line that represents the path followed by light (Pg. 93)
Illuminance
The amount of light arriving at one place per unit area (Pg. 96)
Lens
Piece of glass or another transparent material that either brings together or spreads light rays passing through it; has two opposite surfaces, either both curved or one plane and one curved (Pg. 119)
Retina
Special lining on the back of your eye; when light hits the retina, receptor cells send messages to the brain, which are translated into an image (Pg. 126)
Aperture
Hole or opening that lets light in a camera (Pg. 125)
Diaphragm
Part that changes the size of the aperture of camera’s lens; it varies the amount of light that reaches the film or photosensitive elements (Pg. 126)
Pupil
Opening in the eye that lets light in (Pg. 125)
CCD Matrix
A combination of Charged Coupled Device cells in a camera which has a similar function to the retina in the eye (Pg 126)
Iris
Band of muscle in your eye that controls the size of the pupil and the amount of light entering your eye (Pg. 125)
Addition Model of Colour
Theory that explains what happens when coloured lights are mixed together to produce colours (Pg. 143)
Subtraction Model of Colour
Theory that explains what happens when coloured pigments (paints) are mixed together; each primary colour of pigment absorbs, or subtracts, a primary colour of light and reflects the other two (Pg. 146)
Amplitude
Height of the wave from its middle rest position to its highest point (Pg. 151)
Frequency
Number of times a wave source or medium vibrates in a given unit of time (Pg. 151)
Bioluminescence
Light emitted from a living organism as a result of naturally occurring chemical reactions inside the organism (Pg. 161)
Chemiluminescence
The production of light through a chemical reaction (Pg. 161)
Phosphorescence
A glow caused by the absorption and then release of stored light (Pg. 162)
Organic Light-emitting Diode (OLED)
A source of electroluminescence in which the light-emitting layer is an organic compound (Pg. 162)
Electroluminescence
The emission of light as a result of an electric current being passed through a material (Pg. 162)
Compact Fluorescent Lamp (CFL)
Source of artificial light; an opaque tube coated on the inside with a fluorescent material; uses ultraviolet light waves to make the fluorescent coating produce light (Pg. 163)
Light-emitting Diode (LED)
Source of artificial light where light is produced by passing electricity through a semiconductor material (Pg. 163)
Ray Diagram
Diagram used to represent how light travels; each ray has an arrow to shoe the direction of travel (Pg. 93)
Shadow
Area of reduced light created whenever an opaque object blocks the path of light (Pg. 33)
Law of Reflection
Angle of incidence of a wave hitting a surface equals the angle of reflection (Pg. 102)
Focal Point
The point at which the light rays forming an image come together in focus (Pg. 127)
Primary Colours of Light
Red, green, and blue light; adding these colours of light produces white light (Pg. 143)
Normal (in math/science)
90 degrees to the base
Rods
specialized eye cells that process shades of black & white
Cones
specialiced eye cells that process color
