Optics Flashcards
What is light from incandescence?
The process of producing light as a result of high temperatures. He did objects begin to glow and eventually emit light
How do incandescent lightbulbs work?
Theremins wire made of tungsten, glows as electricity passes through it and becomes so hot it gives the visible light light. Only 5 to 10% of electricity is converted to like energy, the rest is converted to infrared light which can be felt as heat Which means that this is a very inefficient method of producing light. Thomas Addison was the inventor
How do you get light from electric discharge?
Flight from electric discharge is light that is produced by an electric current passing through a gas. electricity causes gas to glow. The electric energy excites the atoms, causing them to jump into a higher orbit (or energy level). When they jump down they give off energy as electromagnet radiation.
Neon, argon, helium, and krypton produce what light?
Ne: Red
Ar: violet/blue
He: gold
Kr: off white
How does light by phosphorescence work?
Materials are coated with phosphorus which absorbs light energy, especially UV light. The materials keep some of the energy and release some as visible light of lower energy. The rates of energy loss depends on the material and may take seconds today. For this reason they’re often called “glow-in-the-dark” materials
How does light from phosphorescence work?
An object absorbs UV light and immediately releases the energy as visible light.
What are some examples of fluorescence?
Laundry detergent have added fluorescent dyes. Therefore shirts tend to glow slightly which is apparent in even visible light since it contains a small amount of UV light. Highlighter pens, fluorescent lights
How do fluorescent lights work?
Uses both electrical discharge inflorescence. Light tube is filled with very low-pressure mercury vapor and the inner surface of the tube is coated with a fluorescent material. The electricity causes the Mercury atoms to emit UV light which strikes the fluorescent inner surface, resulting in the production of visible light.
What are the advantages of fluorescent lights?
They are 4 to 5 times more efficient than incandescent lightbulbs. They produce less heat, use less electricity and the bulbs last longer.
What are the disadvantages of fluorescent lights?
They are more expensive and contain mercury, which is toxic, so they cannot be disposed of with household waste, they must be taken to an appropriate recycling center.
How does the light from chemiluminescence work?
Chemiluminescence is the production of light as a direct byproduct of a chemical reaction. In this method almost no heat is produced.
How do glow sticks work?
Utilizes chemiluminescence. Two chemicals are originally separate in the glow stick, one is in a narrow small glass file in the middle of the glow stick and one is in the main body of the stick. Bending the stick breaks the small glass vial mixing the two chemicals. The chemical reaction produces light.
What are the advantages of glow sticks?
They are inexpensive to make, no electricity required, durable.
What is light from bioluminescence?
Chemiluminescence in living organisms. Enzyme Luciferase is needed for the reaction to occur.
Why do animals use bioluminescence?
Used for protection from predators, two lure pray and to attract mates
What is light from triboluminescence?
Triboluminescence is the production of light when certain crystals are scratched, crushed for rubbed
What is lights from a light emitting diode?
An electronic device that allows current to flow in only one direction. This is achieved by using special semiconductors like silicone.
How are LEDs different from incandescent bulbs?
They do not need filament, do not produce as much heat, and are more energy-efficient.
What is geometric optics?
The use of light rays to determine the path of light when it strikes an object
What is incident light?
The light emitted from an object
Define a transparent object
Lets light pass through it and objects behind it to be seen clearly
What is a translucent object?
Allows some light to pass through it but does not clearly show objects behind it
Define an opaque object
Does not allow any light pass through it. All incident light is absorbed or reflected and Objects behind it cannot be seen
Define image
The reproduction of an original object that is produced through the use of light
