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8J Light
Key words
Term | Definition |
---|---|
Image | A picture that forms in a mirror, on a screen, or by looking down a lens |
Opaque | Matter that does not let light through |
Pinhole camera | An image formed when light passes through a tiny hole |
Ray | A narrow beam of light with an arrow showing direction |
Shadow | A place where light cannot get to |
Source | Where a wave begins |
Translucent | Material that lets light through but scatters it |
Transparent | A material that lets light through without scattering it |
Angle of incidence | The angle between an incoming light ray and the normal |
Normal | An imaginary line at right angles to the surface of a mirror or other object where a ray of light hits it |
Angle of reflection | The angle between the normal and the ray of light leaving a mirror |
Plane mirror | A smooth, flat mirror |
Ray box | A piece of equipment that produces a narrow beam of light |
Ray diagram | A diagram that represents the path of light using arrows |
Ray tracing | A method of investigating what happens to light by marking the path of a light ray |
Diffuse reflection | Reflection from a rough surface where the reflected light is scattered in all directions |
Law of reflection | The angle of incidence is equal to the angle of reflection |
Specular reflection | When light is reflected evenly so that all reflected light goes off in the same direction |
Angle of refraction | The angle between the normal and a ray of light that has been refracted |
Converging lens | A lens that makes rays of light come together |
Focal length | The distance between the centre of the lens and the focal point |
Focal point | The place where parallel rays of light are brought together by a converging lens |
Interface | The boundary between two materials |
Lens | A curved piece of glass or other transparent material that can change the direction of rays of light |
Refraction | The change in direction when light goes from one transparent material to another |
Aperture | A hole in a camera that controls how much light goes to the sensor |
Cone cell | A cell in the retina that detects different colours of light |
Cornea | The transparent front part of the eye which covers the iris and pupil |
Digital camera | A camera that uses electronics to record an image |
Iris | The coloured part of the eye |
Memory card | Part of a digital camera that stores the images |
Optic nerve | The nerve that takes impulses form the retinal to the brain |
Primary colour | One of three colours (red/green/blue) that are detected by the cone cells |
Pupil | The hole in the front of the eye that light can pass through |
Retina | The back part of the eye that changes light energy into nerve impulses |
Rod cell | The cell in the retina that detects low levels of light |
Secondary colour | A colour made when two primary colours mix (magenta/cyan/yellow) |
Sensor | An instrument that detects something |
Shutter | The part that opens when a picture is taken to allow light to hit the sensor |
Dispersion | The separation of colours in light |
Filter (physics) | Something that only lets certain colours through and absorbs the rest |
Prism | A block of clear colourless material usually triangular |
Spectrum | The seven colour that make up white light |
White light | The combination of primary colours |