Flashcards
Light
Flashcards do conjunto (41)
- 1Define LuminousAn object that emits it's own light e.g. the sun.
- 2Define illuminousAn object that reflects the light of a luminous object e.g. The moon.
- 3Name the three primary colours of lightRed Green Blue
- 4Name the three secondary colours of lightYellow Magenta Cyan
- 5What happens when you mix all the primary colours of light?You get white
- 6Define transparentLight waves can travel through transparent objects. They are see-through.
e.g. glass - 7Define translucentOnly a few light waves can travel through translucent objects. They are kind of see-through.
e.g. Ice - 8Define OpaqueLight waves can't travel through opaque objects. They are not see-through.
e.g. You - 9How do rainbows form?Rainbows are produced when water droplets in the air refract sunlight.
- 10Why do shadows form?LIGHT TRAVELS IN STRAIGHT LINES so when it hits an opaque object, it can go around it so no light can reach the ground behind the object.
- 11If you mix red and green light what do you get?Yellow
- 12If you mix red and blue light what do you get?Magenta
- 13If you mix green and blue light what do you get?Cyan
- 14If you mix red, green and blue what do you get?White
- 15What is the angle of reflection?The angle between the ray hitting the surface and the normal.
- 16What is a virtual image?The picture formed by a lens or an optical instrument such as a camera.
- 17What is a reflected ray?The outgoing ray of light from a mirror or other shiny surface.
- 18What is laterally inverted?A back-to-front image in a plane mirror.
- 19What is the angle of incidence?The angle between the ray that is reflected from a surface and the normal.
- 20What is the normal?A line drawn at right angles to a plane mirror.
- 21What is transmitted light?The light that passes through an object.
- 22What is reflection?The bouncing back of, for example, light or sound from a surface.
- 23What is real image?The image that appears to be behind a mirror.
- 24What is a periscope?An object which uses the law of reflection to overcome a problem.
- 25What is the speed of light?3,000,000 km/s
- 26What is a laser?A device that produces an intense, highly focused beam of light.
- 27What is visible light?The part of the electromagnetic spectrum which can be seen by our eyes.
- 28Light enters our eye through the _______Pupil
- 29The image is projected onto the __________Retina
- 30Light energy is transformed here to chemical energy and the ______ _______ sends nerve impulses to the brain so that we can process the image.Optic nerve
- 31The cornea is the first part of our eye to ______ light rays.refracft
- 32To focus distant objects the lens is _______Thinner
- 33To focus a near object the lens is _______Fatter
- 34The focal length of a lens depends on it's _________Shape
- 35The more _______ a lens is, the more it refracts light and the ________ the focal length.The more ROUNDED a lens is, the more it refracts light and the SHORTER the focal length.
- 36Coloured transparent objects are called ________.Filters
- 37Filters _______ some colours light, but ______ others.Filters TRANSMIT some colours light, but ABSORB others.
- 38How do rough surfaces reflect light?Light reflected is diffused in all directions.
- 39How do plane mirror surfaces reflect light?Light is reflected regularly
- 40What is a PLANE mirror surface?A flat mirror surface
- 41What is the angle of incidence always equal to?The angle of reflection