Light and Optics Topics Unit Final Flashcards
What is a crest?
Highest parts of a wave.
What is a trough?
lowest parts of a wave.
What is the wavelength?
Distance from crest to crest.
What is the amplitude?
Height of the crest or dept of the trough from rest position.
What is frequency?
rate at which the crest and trough move up and down.
How to calculate speed?
Frequency × Wavelength = Speed
What is the Electromagnetic spectrum?
Refers to the whole range of wavelengths of visible and invisible electromagnetic radiation.
What is the Electromagnetic radiation?
All forms of radiant energy; visible light, infrared light, etc.
What are microwaves?
They have the shortest wavelength and highest frequencies of all radio waves. Have 3 characteristics that allow them to be used in cooking:
1) Microwaves are reflected by metal
2) Microwaves pass through glass, paper, plastic, etc
3) Microwaves are absorbed by foods
What are Radio waves?
You can get radio waves by stretching infrared waves. They have a lower wavelength and a lower frequency than visible light.
What is Infrared Radiation?
Red light (wavelength 700 nm) stretched out to 100nm becomes heat radiation or infrared radiation. Invisible to the eye but can be felt with skin. Anything warmer than it’s surroundings emit infrared rays.
What is Ultraviolet Radiation?
Violet part of the visible spectrum. Wavelength of about 200nm. Very energetic. Causes tanning and can do irreparable damage.
What is X-ray?
Shorter wavelengths, higher frequencies. Pass through tissue, skin, muscle, and absorbed by bones. Stays in bone and builds up overtime so you need protection.
What is gamma ray?
Shortest wavelength and highest frequency in electromagnetic spectrum. Result from nuclear reactions. Can kill cells.
Where do natural light sources come from?
The radiation given off by the sun.
Where do artificial light sources come from?
use filaments that uses electricity or halogen gas to glow, or an electronic device that emits light. `
What is incandescent light?
Caused by electrical energy passing through a filament.
What is florescent light?
Caused by electricity passing through a gas.
What is LED?
Light emitting diodes. Light sources that don’t have filaments that burn or get much hot.
What is phosphorescence?
“Glow in the dark” objects. Able to store light when present and release it in the dark.
What is Bioluminescence?
Occurs when living organisms produce their own light from within their bodies. Usually found in organisms that live in the dark. Used to attract prey or scare off predators.
What are Photophores?
Specialized cells of bioluminescent animals.