Lesson 2ª









Light is the electromagnetic energy visible to the human eye. It has the form of a wave and it travels in a straight line at 300.000 km./sec. There are different types of electromagnetic energy and the visible spectrum (commonly known as light) is any form of light we can see.

The different types of electromagnetic energy are:

Gamma rays , X-Rays, Ultraviolet (UV), Visible Spectrum, Infrared, radar waves, TV and Radio Waves.

From the visible spectrum, blue light has the shortest waves (400nm) and red light has the longest waves (700nm). In the middle, we have orange, yellow, and green. The human eye captures different wave lengths and interprets them as colours. White light is a mixture of every wave.


NM: 1 billionth of a meter.


Visible spectrum

Light has 3 basic dimensions:

      • Wave length: perceived by the human eye as the colour of light.
      • Polarization: the angle in which lights vibrates. The human eye rarely perceives this.
      • Intensity: how bright or strong light is.