Fundamental Physics/Light

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Light comes from light sources

Visible light[edit]

Measurement of speed of light[edit]

In vacuum (medium free of air) by Michel Morrison

In air, as electromagnetic radiation by James clerk Maxwell

In general,

Visible light travels at constant speed in air and in vaccum as an electromagnetic wave radiation

Light wave[edit]

James Clerk Maxwell proved that light wave is a radiation of electromagnetic wave travels at speed of visible light . Radiation of electromagnetic wave produces visible light which is visible to human's eyes .

Visible light travels at constant speed C = 3 x 106 m/s of a visible wavelength




Light and Matter[edit]


  • Light interacts with matter in 3 states
Air . Light energy is can be transmitted easily
Liquid . Light energy is partially transmitted
Solid . Light energy is reflected
  • Energy absorbs by matter from interaction with light's energy depend on matter's thickness and its color
Observation shows that Dark and thin clothes dry faster than bright and thick clothes


  • Light's speed in vacuum and in air is constant
m /s
  • Light's speed in liquid is relative to speed of light
~ m /s

Energy transfer[edit]

  • Light interacts with matter to create Heat transfer of three phases namely Heat conduction, Heat convection, and Heat radiaton
Heat transfer
Heat conduction Matter absorbs heat energy and create temperature change
Heat convection Matter conducts heat energy to the maximum at threshold frequency

Heat radiation Matter's atom frees its electron from the excess energy above the the maximum energy conduct

In general, light and matter interacts create the following effects

Light effects Definition Illustration
Reflection Light wave is being returns to medium where it comes from Ray Diagram 2.PNG
Refraction Light wave is partially transmitted Ray Diagram.PNG
Diffraction Light wave travels through narrow slits Two-Slit Diffraction.png
Dispersion Light decopose into its composite color lights Two-Slit Diffraction.png
Interference 2 waves heading toward each other spperimpose to create wave interferfence Two-Slit Diffraction.png

Color Lights[edit]

Visible light decompose into its composites color lights when light travels through prism

Light dispersion conceptual waves350px.gif

There are 6 colors are observed Red, Orange, Yellow, Green, Blue, Violet

Color Angle of fraction Wavelength

Matter's Shadow Image[edit]

Electric Light[edit]

When magnetic matter interacts with electricity can create visible light as photon light of electromagnetic oscillation wave radiation