Light Flashcards
Light
Light is a form of energy that travels in waves through empty space and materials
Electromagnetic waves carry both ____ and _____ energy.
Magnetic, electrical
Electromagnetic radiation can be described in terms of a stream of massless articles, called _____, each travelling in a wave-like pattern at the speed of light.
photons
Frequency
The number of crests that pass a given point within one second
Wavelength
The distance between crests
Crests
A crest is a point on a surface wave where the displacement of the medium is at a maximum.
Trough
the portion of a wave, such as a light wave, in which the amplitude lies below its average value.
Energy
An electromagnetic wave can also be described in terms of its energy - in units of electron volts (eV)
eV
Electron volts
Types of electromagnetic waves, order in longest to shortest
Radio waves, microwaves, infrared radiation, visible light, UV radiation, X-rays, gamma rays
Moving along the spectrum from long to short wavelengths, energy ______ as the wavelength shortens.
increases
Incandescence
Light energy given off by an object because it is very hot
Luminescence
Light energy given off without a heat source
Flourescence
Light emitted during exposure of the source to ultraviolet light, but only when the energy source is present
Phosphorescence
Light emitted during exposure of the source to ultraviolet light, even after the source is removed
Chemiluminescence
Light energy produced by a chemical reaction
Bioluminescence
Light energy produced by a biochemical reaction in a living organism
Reflection
Process in which light “bounces off” the surface of an object and travels in another direction.
Specular (Regular) Reflection
Reflection of light off a smooth shiny surface
Diffuse Reflection
Reflection of light off a bumpy, rough, surface
Absorbtion
Process in which light energy remains in the object that it hits, and the light energy is converted into heat.
Transmission
Process in which light travels through an object and continues travelling upon exiting the object
Light from the sun
- Most abundant source of light
- Hydrogen atoms in the sun collide and sometimes form helium
- Energy is released in the form of light
Emission of light
When electrons collide with other atoms, this causes the outer electrons to get pushed to a higher level. When the electron returns to the lower energy level, the energy difference is given off as a photon of light. (Electromagnetic radiation)
